There is a bug on framebufer and vt,kernel will die on some platform when switch from vga mode to framebuffer mode. The reason of this bug is that bind_con_driver reset vc->vc_origin to (unsigned long)vc->vc_screenbuf. 1.The description bellow is my test on mips platform. On this platform vga memory is at 0xb00b8000 (0xb0000000 is pci memory 0)，kernel memory is from 0x80000000~0x8fffffff. on include/asm-mips/vga.h #define VGA_MAP_MEM(x, s) (0xffffffffb0000000L + (unsigned long)(x)) on drivers/video/console/vgacon.c static const char *vgacon_startup(void) { ... vga_vram_base = VGA_MAP_MEM(vga_vram_base, vga_vram_size); vga_vram_end = vga_vram_base + vga_vram_size; ... } Here vga_vram_base will be 0xb00b8000. static int vgacon_set_origin(struct vc_data *c) { if (vga_is_gfx || /* We don't play origin tricks in graphic modes */ (console_blanked && !vga_palette_blanked)) /* Nor we write to blanked screens */ return 0; /*---------here set vc_origin,which is not releated to vc->vc_screenbuf here. ---------*/ c->vc_origin = c->vc_visible_origin = vga_vram_base; vga_set_mem_top(c); vga_rolled_over = 0; return 1; } Here vc_origin will be 0xb00b8000. ./drivers/char/vt.c static void set_origin(struct vc_data *vc) { WARN_CONSOLE_UNLOCKED(); if (!CON_IS_VISIBLE(vc) || !vc->vc_sw->con_set_origin || !vc->vc_sw->con_set_origin(vc)) vc->vc_origin = (unsigned long)vc->vc_screenbuf; vc->vc_visible_origin = vc->vc_origin; /*---------here set vc_src_end ---------*/ vc->vc_scr_end = vc->vc_origin + vc->vc_screenbuf_size; vc->vc_pos = vc->vc_origin + vc->vc_size_row * vc->vc_y + 2 * vc->vc_x; } Here vc.vc_scr_end will be 0xb00b8fa0. So before framebuffer take over console,vc=0x81081340 vc.vc_origin=0xb00b8000,vc.vc_scr_end=0xb00b8fa0. When kernel boot,framebuffer take over vga's console: backtrace like this: [<80430640>] vc_do_resize+0x2d4/0x4e4 [<80430874>] vc_resize+0x24/0x3c [<804413ac>] fbcon_init+0x358/0x4d8 [<80430148>] visual_init+0x198/0x224 bind_con_driver [<80432fa4>] take_over_console+0x508/0x6e8 [<80440400>] fbcon_takeover+0x88/0xf4 [<80446bac>] fbcon_event_notify+0x46c/0x99c [<8025f060>] notifier_call_chain+0x64/0xbc [<8025f3f4>] __blocking_notifier_call_chain+0x5c/0x98 [<8025f444>] blocking_notifier_call_chain+0x14/0x2c [<80439eec>] register_framebuffer+0x1e8/0x218 [<8020ff1c>] sisfb_probe+0x2140/0x224c [<80414a00>] pci_device_probe+0x70/0xb4 [<80483874>] driver_probe_device+0x174/0x2b0 [<80483aa4>] __driver_attach+0x54/0x98 [<804824a8>] bus_for_each_dev+0x60/0xb0 [<80482df4>] bus_add_driver+0xc8/0x280 [<8048409c>] driver_register+0xb4/0x178 [<80414728>] __pci_register_driver+0x58/0xb8 [<8070e460>] sisfb_init+0x89c/0x8e4 [<80219350>] __kprobes_text_end+0x68/0x1c4 [<806f8c0c>] kernel_init+0xa8/0x134 [<8021b9e4>] kernel_thread_helper+0x1c/0x24 static int bind_con_driver(const struct consw *csw, int first, int last, int deflt) { ... /* notice that here change vc_origin to vc_screenbuf,wrong! */ vc->vc_origin = (unsigned long)vc->vc_screenbuf; visual_init(vc, i, 0); ... } for vgacon in my test: vc=0x81081340 origin=0xb00b8000,end=0xb00b8fa0 after here change to vc=0x81081340,origin=0x810814a0,end=0xb00b8fa0 then go to see vc_do_resize,visual_init will call it. static int vc_do_resize(struct tty_struct *tty, struct tty_struct *real_tty, struct vc_data *vc, unsigned int cols, unsigned int lines) { unsigned long old_origin, new_origin, new_scr_end, rlth, rrem, err = 0; unsigned int old_cols, old_rows, old_row_size, old_screen_size; unsigned int new_cols, new_rows, new_row_size, new_screen_size; unsigned int end, user; ... end = (old_rows > new_rows) ? old_origin + (old_row_size * new_rows) : vc->vc_scr_end; ... /* here for vgacon: old_origin=810814a0,end=b00b8fa0,vc->vc_origin=810814a0 the code bellow will copy memory from 0x810814a0 to 0xb00b8fa0, this will cover kernel code,kernel died here. */ while (old_origin < end) { scr_memcpyw((unsigned short *) new_origin, (unsigned short *) old_origin, rlth); if (rrem) scr_memsetw((void *)(new_origin + rlth), vc->vc_video_erase_char, rrem); old_origin += old_row_size; new_origin += new_row_size; } ... } the code bellow will above copy memory from 0x810814a0 to 0xb00b8fa0,this will cover kernel code,kernel died here. The test I have done is on mips 32bit kernel. On 64bit kernel,kernel will run well. When I look close at the code,I found that variable end is defined as integer,but old_origin is unsigned long. On 64bit kernel long is 64bit,int is 32bit,so old_origin is large than end,so kernel jump over the dead code. So I say: 2.The kernel code may be not very clean, In function vc_do_resize,old_origin, new_origin, new_scr_end is unsigned long type,but end is int type. According include/linux/console_struct.h,they all should be unsigned long. struct vc_data { unsigned short vc_num; /* Console number */ unsigned int vc_cols; /* [#] Console size */ unsigned int vc_rows; unsigned int vc_size_row; /* Bytes per row */ unsigned int vc_scan_lines; /* # of scan lines */ unsigned long vc_origin; /* [!] Start of real screen */ unsigned long vc_scr_end; /* [!] End of real screen */ unsigned long vc_visible_origin; /* [!] Top of visible window */ unsigned int vc_top, vc_bottom; /* Scrolling region */ const struct consw *vc_sw; unsigned short *vc_screenbuf; ... } That's all. -- QiaoChong(Chong Qiao) qiaochong@loongson.cn
Created attachment 26696 [details] 0001-fix-vc-vc_origin-on-take_over_console.patch 0001-fix-vc-vc_origin-on-take_over_console.patch
Created attachment 26697 [details] 0002-Variable-end-on-vc_do_resize-should-be-unsigned-long.patch
Please don't send patches via bugzilla - it causes lots of problems with our usual patch management and review processes. Please send this patch via email as per Documentation/SubmittingPatches. Suitable recipients for these patches are Andrew Morton <akpm@linux-foundation.org> linux-kernel@vger.kernel.org Thanks.
Thank you for your reply. Greg KH Said: > On Thu, Jun 17, 2010 at 06:46:56PM +0800, qiaochong wrote: > >> kernel will die on some platform when switch from vga mode to framebuffer >> mode. >> > > What platform does this die on? With what kernel version? > > The platform is loongson 2f cpu's development board. Loongson 2f is a mips64el cpu. The kernel version is 2.6.27.7, mipsel 32bit kernel. The graphic card I use is sis V2. >> The reason of this bug is that bind_con_driver reset vc->vc_origin to >> (unsigned long)vc->vc_screenbuf. >> On vgacon vc->vc_origin is not releated to vc->vc_screenbuf,if set >> vc->vc_origin to vc->vc_screenbuf,kernel will die on vc_do_resize. >> > > Why does this not show up for everyone else? Is this caused by > something recently changed, or do all older kernels have this problem as > well? > > After read your email,I spent half a day to test kernel 2.6.18.1 and kernel 2.6.27.7. 2.6.18.1 is ok. 2.6.27.7 die. The reason is vgacon_resize on two kernel return different,which cause the kernel's bug is probed on 2.6.27.7. At Bellow is my analysis. 2.6.27.7's boot info: Linux version 2.6.27.7-fl (root@softeam) (gcc version 3.4.6) #14 Fri Jun 18 11:15:25 CST 2010 -00287-gb03d998-dirty busclock=66000000, cpuclock=697320000,memsize=256,highmemsize=1792 console [early0] enabled CPU revision is: 00006303 (ICT Loongson-2) FPU revision is: 00000501 Determined physical RAM map: memory: 10000000 @ 00000000 (usable) Initrd not found or empty - disabling initrd Zone PFN ranges: Normal 0x00000000 -> 0x00004000 Movable zone start PFN for each node early_node_map[1] active PFN ranges 0: 0x00000000 -> 0x00004000 Built 1 zonelists in Zone order, mobility grouping on. Total pages: 16352 Kernel command line: rdinit=/sbin/init console=ttyS0,115200 root=/dev/hda1 Primary instruction cache 64kB, VIPT, direct mapped, linesize 32 bytes. Primary data cache 64kB, 4-way, VIPT, no aliases, linesize 32 bytes Unified secondary cache 512kB 4-way, linesize 32 bytes. PID hash table entries: 1024 (order: 10, 4096 bytes) Console: colour VGA+ 80x25 Dentry cache hash table entries: 32768 (order: 3, 131072 bytes) Inode-cache hash table entries: 16384 (order: 2, 65536 bytes) Memory: 251600k/262144k available (4129k kernel code, 10272k reserved, 992k data, 2080k init, 0k highmem) Calibrating delay loop... 463.87 BogoMIPS (lpj=927744) Security Framework initialized SELinux: Disabled at boot. Mount-cache hash table entries: 2048 net_namespace: 768 bytes NET: Registered protocol family 16 Linux Plug and Play Support v0.97 (c) Adam Belay SCSI subsystem initialized usbcore: registered new interface driver usbfs usbcore: registered new interface driver hub usbcore: registered new device driver usb pci 0000:00:10.0: PME# supported from D1 D2 D3hot pci 0000:00:10.0: PME# disabled via686b fix: ISA bridge via686b fix: ISA bridge done via686b fix: IDE via686b fix: IDE done pci 0000:00:11.4: quirk: region eee0-eeef claimed by vt82c686 SMB ac97 interrupt = 9 ac97 rev=32 Setting sub-vendor ID & device ID sub vendor-device id=47101005 bus: 00 index 0 io port: [4000, ffff] bus: 00 index 1 mmio: [50000000, 7fffffff] NET: Registered protocol family 8 NET: Registered protocol family 20 NET: Registered protocol family 2 IP route cache hash table entries: 4096 (order: 0, 16384 bytes) TCP established hash table entries: 8192 (order: 2, 65536 bytes) TCP bind hash table entries: 8192 (order: 1, 32768 bytes) TCP: Hash tables configured (established 8192 bind 8192) TCP reno registered NET: Registered protocol family 1 audit: initializing netlink socket (disabled) type=2000 audit(1041389669.635:1): initialized VFS: Disk quotas dquot_6.5.1 Dquot-cache hash table entries: 4096 (order 0, 16384 bytes) Installing knfsd (copyright (C) 1996 okir@monad.swb.de). msgmni has been set to 491 io scheduler noop registered io scheduler anticipatory registered io scheduler deadline registered io scheduler cfq registered (default) sisfb: Video ROM not found sisfb: Video RAM at 0x50000000, mapped to 0xc0000000, size 65536k sisfb: MMIO at 0x60000000, mapped to 0xc4080000, size 256k sisfb: Memory heap starting at 64928K, size 32K sisfb: Detected SiS301C video bridge sisfb: CRT1 DDC probing failed sisfb: Default mode is 800x600x8 (60Hz) vc_do_resize:851 vc->vc_origin=b00b8000,vc->vc_scr_end=b00b8fa0 Call Trace: [<80220250>] dump_stack+0x8/0x40 [<804337e8>] vc_do_resize+0x14c/0x514 [<80433bd4>] vc_resize+0x24/0x3c [<80444564>] fbcon_startup+0x334/0x388 [<80435bd8>] register_con_driver+0x11c/0x230 [<80435e3c>] take_over_console+0x40/0x5ec [<80443964>] fbcon_takeover+0x88/0xf4 [<8044a110>] fbcon_event_notify+0x46c/0x99c [<80260594>] notifier_call_chain+0x64/0xbc [<80260928>] __blocking_notifier_call_chain+0x5c/0x98 [<80260978>] blocking_notifier_call_chain+0x14/0x2c [<8043d150>] register_framebuffer+0x1e8/0x218 [<80211550>] sisfb_probe+0x2140/0x224c [<80417d84>] pci_device_probe+0x70/0xb4 [<8048dc34>] driver_probe_device+0x174/0x2b0 [<8048de64>] __driver_attach+0x54/0x98 [<8048c868>] bus_for_each_dev+0x60/0xb0 [<8048d1b4>] bus_add_driver+0xc8/0x280 [<8048e45c>] driver_register+0xb4/0x178 [<80417aac>] __pci_register_driver+0x58/0xb8 [<8071a7b4>] sisfb_init+0x89c/0x8e0 [<8021a380>] __kprobes_text_end+0x68/0x1c4 [<80704c0c>] kernel_init+0xa8/0x134 [<8021ca14>] kernel_thread_helper+0x1c/0x24 vc_do_resize:877 vc->vc_origin=b00b8000,vc->vc_scr_end=b00b8fa0 vc_do_resize:878 vc->vc_sw->con_resize=80442d54 vgacon_resize+0x0/0xbc vc_do_resize:879 new_cols=100,new_rows=37 vc_do_resize:881 after resize_screen,error=-22 bind_con_driver:3079 old vc_origin=b00b8000,vc_screenbuf=81081420 bind_con_driver:3081 new vc_origin=81081420,vc_screenbuf=81081420,vc->vc_scr_end=b00b8fa0 vc_do_resize:851 vc->vc_origin=81081420,vc->vc_scr_end=b00b8fa0 Call Trace: [<80220250>] dump_stack+0x8/0x40 [<804337e8>] vc_do_resize+0x14c/0x514 [<80433bd4>] vc_resize+0x24/0x3c [<80444910>] fbcon_init+0x358/0x4d8 [<8043348c>] visual_init+0x158/0x1d0 [<8043624c>] take_over_console+0x450/0x5ec [<80443964>] fbcon_takeover+0x88/0xf4 [<8044a110>] fbcon_event_notify+0x46c/0x99c [<80260594>] notifier_call_chain+0x64/0xbc [<80260928>] __blocking_notifier_call_chain+0x5c/0x98 [<80260978>] blocking_notifier_call_chain+0x14/0x2c [<8043d150>] register_framebuffer+0x1e8/0x218 [<80211550>] sisfb_probe+0x2140/0x224c [<80417d84>] pci_device_probe+0x70/0xb4 [<8048dc34>] driver_probe_device+0x174/0x2b0 [<8048de64>] __driver_attach+0x54/0x98 [<8048c868>] bus_for_each_dev+0x60/0xb0 [<8048d1b4>] bus_add_driver+0xc8/0x280 [<8048e45c>] driver_register+0xb4/0x178 [<80417aac>] __pci_register_driver+0x58/0xb8 [<8071a7b4>] sisfb_init+0x89c/0x8e0 [<8021a380>] __kprobes_text_end+0x68/0x1c4 [<80704c0c>] kernel_init+0xa8/0x134 [<8021ca14>] kernel_thread_helper+0x1c/0x24 vc_do_resize:877 vc->vc_origin=81081420,vc->vc_scr_end=b00b8fa0 vc_do_resize:878 vc->vc_sw->con_resize=804461a0 fbcon_resize+0x0/0x528 vc_do_resize:879 new_cols=100,new_rows=37 vc_do_resize:881 after resize_screen,error=0 vc_do_resize:897 old_origin=81081420,new_origin=8e124000,new_scr_end=8e125ce8 vc_do_resize:925 before scr_memcpyw:old_origin=81081420,end=b00b8fa0,vc->vc_scr_end=b00b8fa0 kernel die here. Then see source code on 2.6.27.7: ./drivers/char/vt.c 108 void prom_printf(char *fmt, ...); 109 #define mydebug(s...) prom_printf("%s:%d ",__FUNCTION__,__LINE__); prom_printf(s) ... 826 static int vc_do_resize(struct tty_struct *tty, struct tty_struct *real_tty, 827 struct vc_data *vc, unsigned int cols, unsigned int lines) 828 { ... 846 new_cols = (cols ? cols : vc->vc_cols); 847 new_rows = (lines ? lines : vc->vc_rows); 848 new_row_size = new_cols << 1; 849 new_screen_size = new_row_size * new_rows; 850 851 mydebug("vc->vc_origin=%08x,vc->vc_scr_end=%08x\n",vc->vc_origin,vc->vc_scr_end); 852 if (new_cols == vc->vc_cols && new_rows == vc->vc_rows) 853 return 0; ... 877 mydebug("vc->vc_origin=%08x,vc->vc_scr_end=%08x\n",vc->vc_origin,vc->vc_scr_end); 878 mydebug("vc->vc_sw->con_resize=%08x %pS\n",vc->vc_sw->con_resize,vc->vc_sw->con_resize); 879 mydebug("new_cols=%d,new_rows=%d\n",new_cols,new_rows); 880 err = resize_screen(vc, new_cols, new_rows, user); 881 mydebug("after resize_screen,error=%d\n",err); 882 if (err) { 883 kfree(newscreen); 884 return err; 885 } 886 887 vc->vc_rows = new_rows; 888 vc->vc_cols = new_cols; 889 vc->vc_size_row = new_row_size; 890 vc->vc_screenbuf_size = new_screen_size; ... 925 mydebug("before scr_memcpyw:old_origin=%08x,end=%08x,vc->vc_scr_end=%08x\n",old_origin,end,vc->vc_scr_end); 926 while (old_origin < end) { 927 scr_memcpyw((unsigned short *) new_origin, 928 (unsigned short *) old_origin, rlth); 929 if (rrem) 930 scr_memsetw((void *)(new_origin + rlth), 931 vc->vc_video_erase_char, rrem); 932 old_origin += old_row_size; 933 new_origin += new_row_size; 934 } ... } ... 3015 static int bind_con_driver(const struct consw *csw, int first, int last, 3016 int deflt) 3017 { ... 3078 vc->vc_sw->con_deinit(vc); 3079 mydebug("old vc_origin=%08x,vc_screenbuf=%08x\n",vc->vc_origin,vc->vc_screenbuf,vc->vc_scr_end); 3080 vc->vc_origin = (unsigned long)vc->vc_screenbuf; 3081 mydebug("new vc_origin=%08x,vc_screenbuf=%08x,vc->vc_scr_end=%08x\n",vc->vc_origin,vc->vc_screenbuf,vc->vc_scr_end); 3082 visual_init(vc, i, 0); 3083 set_origin(vc); 3084 mydebug("after set_origin vc_origin=%08x,vc_screenbuf=%08x,vc->vc_scr_end=%08x\n",vc->vc_origin,vc->vc_screenbuf ,vc->vc_scr_end); 3085 update_attr(vc); 3086 ... } If resize_screen on line 880 return 0,then vc->vc_rows and vc->vc_cols will be set to new value. Next time in visual_init call resize_screen will return on line 853,So will not die although old_origin=81081420,end=b00b8fa0,vc->vc_scr_end=b00b8fa0. If resize_screen on line 880 return !0,next time in visual_init call resize_screen will die on 926,because copying from 0x81081420 till 0xb00b8fa0 to new_origin will cover kernel area. If I do not run line 882,883 882 if (err) { 883 // kfree(newscreen); 884 // return err; 885 } Then boot is ok as bellow: Linux version 2.6.27.7-fl (root@softeam) (gcc version 3.4.6) #15 Fri Jun 18 11:42:39 CST 2010 -00287-gb03d998-dirty busclock=66000000, cpuclock=697340000,memsize=256,highmemsize=1792 console [early0] enabled CPU revision is: 00006303 (ICT Loongson-2) FPU revision is: 00000501 Determined physical RAM map: memory: 10000000 @ 00000000 (usable) Initrd not found or empty - disabling initrd Zone PFN ranges: Normal 0x00000000 -> 0x00004000 Movable zone start PFN for each node early_node_map[1] active PFN ranges 0: 0x00000000 -> 0x00004000 Built 1 zonelists in Zone order, mobility grouping on. Total pages: 16352 Kernel command line: rdinit=/sbin/init console=ttyS0,115200 root=/dev/hda1 Primary instruction cache 64kB, VIPT, direct mapped, linesize 32 bytes. Primary data cache 64kB, 4-way, VIPT, no aliases, linesize 32 bytes Unified secondary cache 512kB 4-way, linesize 32 bytes. PID hash table entries: 1024 (order: 10, 4096 bytes) Console: colour VGA+ 80x25 Dentry cache hash table entries: 32768 (order: 3, 131072 bytes) Inode-cache hash table entries: 16384 (order: 2, 65536 bytes) Memory: 251600k/262144k available (4129k kernel code, 10272k reserved, 992k data, 2080k init, 0k highmem) Calibrating delay loop... 463.87 BogoMIPS (lpj=927744) Security Framework initialized SELinux: Disabled at boot. Mount-cache hash table entries: 2048 net_namespace: 768 bytes NET: Registered protocol family 16 Linux Plug and Play Support v0.97 (c) Adam Belay SCSI subsystem initialized usbcore: registered new interface driver usbfs usbcore: registered new interface driver hub usbcore: registered new device driver usb pci 0000:00:10.0: PME# supported from D1 D2 D3hot pci 0000:00:10.0: PME# disabled via686b fix: ISA bridge via686b fix: ISA bridge done via686b fix: IDE via686b fix: IDE done pci 0000:00:11.4: quirk: region eee0-eeef claimed by vt82c686 SMB ac97 interrupt = 9 ac97 rev=32 Setting sub-vendor ID & device ID sub vendor-device id=47101005 bus: 00 index 0 io port: [4000, ffff] bus: 00 index 1 mmio: [50000000, 7fffffff] NET: Registered protocol family 8 NET: Registered protocol family 20 NET: Registered protocol family 2 IP route cache hash table entries: 4096 (order: 0, 16384 bytes) TCP established hash table entries: 8192 (order: 2, 65536 bytes) TCP bind hash table entries: 8192 (order: 1, 32768 bytes) TCP: Hash tables configured (established 8192 bind 8192) TCP reno registered NET: Registered protocol family 1 audit: initializing netlink socket (disabled) type=2000 audit(1041391376.635:1): initialized VFS: Disk quotas dquot_6.5.1 Dquot-cache hash table entries: 4096 (order 0, 16384 bytes) Installing knfsd (copyright (C) 1996 okir@monad.swb.de). msgmni has been set to 491 io scheduler noop registered io scheduler anticipatory registered io scheduler deadline registered io scheduler cfq registered (default) sisfb: Video ROM not found sisfb: Video RAM at 0x50000000, mapped to 0xc0000000, size 65536k sisfb: MMIO at 0x60000000, mapped to 0xc4080000, size 256k sisfb: Memory heap starting at 64928K, size 32K sisfb: Detected SiS301C video bridge sisfb: CRT1 DDC probing failed sisfb: Default mode is 800x600x8 (60Hz) vc_do_resize:851 vc->vc_origin=b00b8000,vc->vc_scr_end=b00b8fa0 Call Trace: [<80220250>] dump_stack+0x8/0x40 [<804337e8>] vc_do_resize+0x14c/0x500 [<80433bc0>] vc_resize+0x24/0x3c [<80444550>] fbcon_startup+0x334/0x388 [<80435bc4>] register_con_driver+0x11c/0x230 [<80435e28>] take_over_console+0x40/0x5ec [<80443950>] fbcon_takeover+0x88/0xf4 [<8044a0fc>] fbcon_event_notify+0x46c/0x99c [<80260594>] notifier_call_chain+0x64/0xbc [<80260928>] __blocking_notifier_call_chain+0x5c/0x98 [<80260978>] blocking_notifier_call_chain+0x14/0x2c [<8043d13c>] register_framebuffer+0x1e8/0x218 [<80211550>] sisfb_probe+0x2140/0x224c [<80417d84>] pci_device_probe+0x70/0xb4 [<8048dc1c>] driver_probe_device+0x174/0x2b0 [<8048de4c>] __driver_attach+0x54/0x98 [<8048c850>] bus_for_each_dev+0x60/0xb0 [<8048d19c>] bus_add_driver+0xc8/0x280 [<8048e444>] driver_register+0xb4/0x178 [<80417aac>] __pci_register_driver+0x58/0xb8 [<8071a7b4>] sisfb_init+0x89c/0x8e0 [<8021a380>] __kprobes_text_end+0x68/0x1c4 [<80704c0c>] kernel_init+0xa8/0x134 [<8021ca14>] kernel_thread_helper+0x1c/0x24 vc_do_resize:877 vc->vc_origin=b00b8000,vc->vc_scr_end=b00b8fa0 vc_do_resize:878 vc->vc_sw->con_resize=80442d40 vgacon_resize+0x0/0xbc vc_do_resize:879 new_cols=100,new_rows=37 vc_do_resize:881 after resize_screen,error=-22 vc_do_resize:897 old_origin=b00b8000,new_origin=8e124000,new_scr_end=8e125ce8 vc_do_resize:925 before scr_memcpyw:old_origin=b00b8000,end=b00b8fa0,vc->vc_scr_end=b00b8fa0 bind_con_driver:3079 old vc_origin=b00b8000,vc_screenbuf=8e124000 bind_con_driver:3081 new vc_origin=8e124000,vc_screenbuf=8e124000,vc->vc_scr_end=b00b9ce8 vc_do_resize:851 vc->vc_origin=8e124000,vc->vc_scr_end=b00b9ce8 bind_con_driver:3084 after set_origin vc_origin=8e124000,vc_screenbuf=8e124000,vc->vc_scr_end=8e125ce8 Console: switching to colour frame buffer device 100x37 sisfb: 2D acceleration is enabled, y-panning enabled (auto-max) fb0: SiS 315PRO frame buffer device version 1.8.9 sisfb: Copyright (C) 2001-2005 Thomas Winischhofer isapnp: Scanning for PnP cards... isapnp: No Plug & Play device found [drm] Initialized drm 1.1.0 20060810 Serial: 8250/16550 driver16 ports, IRQ sharing disabled serial8250.0: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550Aconsole handover: boot [early0] -> real [ttyS0] serial8250.0: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A brd: module loaded Intel(R) PRO/1000 Network Driver - version 7.3.20-k3-NAPI Copyright (c) 1999-2006 Intel Corporation. e100: Intel(R) PRO/100 Network Driver, 3.5.23-k4-NAPI e100: Copyright(c) 1999-2006 Intel Corporation 8139too Fast Ethernet driver 0.9.28 eth0: RealTek RTL8139 at 0xc4008000, 00:0a:eb:56:5e:01, IRQ 36 Linux video capture interface: v2.00 Uniform Multi-Platform E-IDE driver Driver 'sd' needs updating - please use bus_type methods mice: PS/2 mouse device common for all mice usbcore: registered new interface driver hiddev usbcore: registered new interface driver usbhid usbhid: v2.6:USB HID core driver TCP bic registered NET: Registered protocol family 17 RPC: Registered udp transport module. RPC: Registered tcp transport module. begin to find the vga mem range find the frame buffer:start=50000000,end=5fffffff Freeing unused kernel memory: 2080k freed init started: BusyBox v1.11.3 (2010-03-31 20:49:53 CST) starting pid 305, tty '': '/etc/init.d/rcS' eth0: link up, 100Mbps, full-duplex, lpa 0x45E1 Please press Enter to activate this console. starting pid 314, tty '': '-/bin/sh' Loongson2@[\w]> You can see that size is updated on first vc_do_resize: vc_do_resize:925 before scr_memcpyw:old_origin=b00b8000,end=b00b8fa0,vc->vc_scr_end=b00b8fa0 On visual_init call vc_do_resize return on line 853: vc_do_resize:851 vc->vc_origin=8e124000,vc->vc_scr_end=b00b9ce8 bind_con_driver:3084 after set_origin vc_origin=8e124000,vc_screenbuf=8e124000,vc->vc_scr_end=8e125ce8 then run set_origin ,after set_origin bind_con_driver:3084 after set_origin vc_origin=8e124000,vc_screenbuf=8e124000,vc->vc_scr_end=8e125ce8 Then see boot info on linux 2.6.18.1: Booting Linux kernel... Godson 2F Evaluation Board Linux version 2.6.18.1-gf0f74d7d-dirty (root@softeam) (gcc version 3.4.6) #8 Fri Jun 18 11:16:39 CST 2010 -gf0f74d7d-dirty busclock=66000000, cpuclock=697340000,memsize=256,highmemsize=1792 CPU revision is: 00006303 FPU revision is: 00000501 Determined physical RAM map: memory: 0ff00000 @ 00100000 (usable) Built 1 zonelists. Total pages: 16384 Kernel command line: rdinit=/sbin/init console=ttyS0,115200 root=/dev/hda1 Primary instruction cache 64kB, physically tagged, 4-way, linesize 32 bytes. Primary data cache 64kB, 4-way, linesize 32 bytes. Unified secondary cache 512kB 4-way, linesize 32 bytes. Synthesized TLB refill handler (19 instructions). Synthesized TLB load handler fastpath (31 instructions). Synthesized TLB store handler fastpath (31 instructions). Synthesized TLB modify handler fastpath (30 instructions). init_IRQ done. PID hash table entries: 2048 (order: 11, 8192 bytes) Using 348.670 MHz high precision timer. Console: colour VGA+ 80x25 Dentry cache hash table entries: 32768 (order: 3, 131072 bytes) Inode-cache hash table entries: 16384 (order: 2, 65536 bytes) Memory: 251312k/261120k available (4476k kernel code, 9568k reserved, 1035k data, 2064k init, 0k highmem) Mount-cache hash table entries: 2048 Checking for 'wait' instruction... unavailable. NET: Registered protocol family 16 SCSI subsystem initialized usbcore: registered new driver usbfs usbcore: registered new driver hub via686b fix: ISA bridge via686b fix: ISA bridge done via686b fix: IDE via686b fix: IDE done PCI quirk: region eee0-eeef claimed by vt82c686 SMB ac97 interrupt = 9 ac97 rev=32 Setting sub-vendor ID & device ID sub vendor-device id=47101005 can not assign bus 0x0,dev 0x11,func 0x4 NET: Registered protocol family 2 IP route cache hash table entries: 2048 (order: -1, 8192 bytes) TCP established hash table entries: 8192 (order: 1, 32768 bytes) TCP bind hash table entries: 4096 (order: 0, 16384 bytes) TCP: Hash tables configured (established 8192 bind 4096) TCP reno registered squashfs: version 3.4 (2008/08/26) Phillip Lougher Installing knfsd (copyright (C) 1996 okir@monad.swb.de). fuse init (API version 7.7) Registering unionfs 1.4 unionfs: debugging is not enabled Initializing Cryptographic API io scheduler noop registered io scheduler anticipatory registered io scheduler deadline registered io scheduler cfq registered (default) pci_hotplug: PCI Hot Plug PCI Core version: 0.5 cpcihp_generic: Generic port I/O CompactPCI Hot Plug Driver version: 0.1 cpcihp_generic: not configured, disabling. sisfb: Video ROM not found sisfb: Video RAM at 0x50000000, mapped to 0xc0000000, size 65536k sisfb: MMIO at 0x60000000, mapped to 0xc4080000, size 256k sisfb: Memory heap starting at 64928K, size 32K sisfb: Detected SiS301C video bridge sisfb: CRT1 DDC probing failed sisfb: Default mode is 800x600x8 (60Hz) Call Trace: [<8020a208>] dump_stack+0x18/0x50 [<80465834>] vc_resize+0xe4/0x588 [<80413db0>] fbcon_startup+0x2a8/0x428 [<80467d88>] register_con_driver+0xcc/0x2d0 [<804680bc>] take_over_console+0x40/0x7e0 [<80413304>] fbcon_takeover+0x80/0xf4 [<8041a0f0>] fbcon_event_notify+0x9cc/0xebc [<8023fd14>] notifier_call_chain+0x4c/0x8c [<8023ff90>] blocking_notifier_call_chain+0x34/0x68 [<8040ca94>] register_framebuffer+0x11c/0x1b0 [<8042f3a8>] sisfb_probe+0x19e0/0x258c [<80401a68>] pci_device_probe+0x98/0xc0 [<8047aa24>] driver_probe_device+0x94/0x100 [<8047aea0>] __driver_attach+0x23c/0x320 [<80479640>] bus_for_each_dev+0x60/0xb0 [<8047a130>] bus_add_driver+0xb4/0x1a4 [<80401784>] __pci_register_driver+0x48/0x9c [<80780aa0>] sisfb_init+0x1b0/0x898 [<8020051c>] init+0xac/0x310 [<80204784>] kernel_thread_helper+0x1c/0x24 vc_resize:811 <0>vc->vc_origin=b00b8000,vc->vc_scr_end=b00b8fa0 vc_resize:814 resize_screen=80465504,new_cols=100,new_rows=37,err=0 vc_resize:831 old_origin=b00b8000,new_origin=809b4000,new_scr_end=809b5ce8 vc_resize:858 before scr_memcpyw:old_origin=b00b8000,end=b00b8fa0,vc->vc_scr_end=b00b8fa0 bind_con_driver:2776 old vc_origin=b00b8000,vc_screenbuf=809b4000,vc->vc_scr_end=b00b9ce8 bind_con_driver:2779 new vc_origin=809b4000,vc_screenbuf=809b4000,vc->vc_scr_end=b00b9ce8 bind_con_driver:2782 after set_origin vc_origin=809b4000,vc_screenbuf=809b4000,vc->vc_scr_end=809b5ce8 Console: switching to colour frame buffer device 100x37 sisfb: 2D acceleration is enabled, y-panning enabled (auto-max) fb0: SiS 315PRO frame buffer device version 1.8.9 sisfb: Copyright (C) 2001-2005 Thomas Winischhofer rtc: SRM (post-2000) epoch (2000) detected Real Time Clock Driver v1.12ac Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing disabled serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A RAMDISK driver initialized: 16 RAM disks of 40960K size 1024 blocksize loop: loaded (max 8 devices) Intel(R) PRO/1000 Network Driver - version 7.1.9-k4 Copyright (c) 1999-2006 Intel Corporation. e100: Intel(R) PRO/100 Network Driver, 3.5.10-k2-NAPI e100: Copyright(c) 1999-2005 Intel Corporation 8139too Fast Ethernet driver 0.9.27 eth0: RealTek RTL8139 at 0xc4008000, 00:0a:eb:56:5e:01, IRQ 20 dmfe: Davicom DM9xxx net driver, version 1.36.4 (2002-01-17) winbond-840.c:v1.01-d (2.4 port) Nov-17-2001 Donald Becker <becker@scyld.com> http://www.scyld.com/network/drivers.html uli526x: ULi M5261/M5263 net driver, version 0.9.3 (2005-7-29) Uniform Multi-Platform E-IDE driver Revision: 7.00alpha2 ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx VP_IDE: IDE controller at PCI slot 0000:00:11.1 PCI: VIA IRQ fixup for 0000:00:11.1, from 14 to 0 VP_IDE: chipset revision 16 VP_IDE: not 100% native mode: will probe irqs later VP_IDE: VIA vt82c686a (rev 22) IDE UDMA66 controller on pci0000:00:11.1 ide0: BM-DMA at 0x4cc0-0x4cc7, BIOS settings: hda:pio, hdb:pio ide1: BM-DMA at 0x4cc8-0x4ccf, BIOS settings: hdc:pio, hdd:pio NFTL driver: nftlcore.c $Revision: 1.98 $, nftlmount.c $Revision: 1.41 $ INFTL: inftlcore.c $Revision: 1.19 $, inftlmount.c $Revision: 1.18 $ loongson flash driver Found: SST 39LF040 loongson bootrom memory: Found 1 x8 devices at 0x0 in 8-bit bank number of JEDEC chips: 1 cfi_cmdset_0002: Disabling erase-suspend-program due to code brokenness. rfd_ftl: no RFD magic found in 'loongson bootrom memory' ftl_cs: FTL header not found. ftl_cs: FTL header corrupt! block2mtd: version $Revision: 1.30 $ usbmon: debugfs is not available USB Universal Host Controller Interface driver v3.0 uhci_hcd 0000:00:11.2: UHCI Host Controller uhci_hcd 0000:00:11.2: new USB bus registered, assigned bus number 1 uhci_hcd 0000:00:11.2: irq 11, io base 0x00004c80 usb usb1: configuration #1 chosen from 1 choice hub 1-0:1.0: USB hub found hub 1-0:1.0: 2 ports detected uhci_hcd 0000:00:11.3: UHCI Host Controller uhci_hcd 0000:00:11.3: new USB bus registered, assigned bus number 2 uhci_hcd 0000:00:11.3: irq 10, io base 0x00004ca0 usb usb2: configuration #1 chosen from 1 choice hub 2-0:1.0: USB hub found hub 2-0:1.0: 2 ports detected Initializing USB Mass Storage driver... usb 2-1: new full speed USB device using uhci_hcd and address 2 usb 2-1: configuration #1 chosen from 1 choice scsi0 : SCSI emulation for USB Mass Storage devices usbcore: registered new driver usb-storage USB Mass Storage support registered. usbcore: registered new driver usbhid /mnt/hda2/work/linux-2.6.18/drivers/usb/input/hid-core.c: v2.6:USB HID core driver serio: i8042 AUX port at 0x60,0x64 irq 12 serio: i8042 KBD port at 0x60,0x64 irq 1 mice: PS/2 mouse device common for all mice Via 686a/8233/8235 audio driver 1.9.1-ac4-2.5 ac97_codec: AC97 Audio codec, id: ALG112 (Unknown) via82cxxx: board #1 at 0x4400, IRQ 9 Advanced Linux Sound Architecture Driver Version 1.0.12rc1 (Thu Jun 22 13:55:50 2006 UTC). atkbd.c: keyboard reset failed on isa0060/serio1 atkbd.c: keyboard reset failed on isa0060/serio0 VIA 82xx Modem: probe of 0000:00:11.6 failed with error -13 ALSA device list: No soundcards found. TCP bic registered NET: Registered protocol family 1 NET: Registered protocol family 17 vga:start=50000000,end=5fffffff Freeing unused kernel memory: 2064k freed init started: BusyBox v1.11.3 (2010-03-31 20:49:53 CST) starting pid 803, tty '': '/etc/init.d/rcS' bonito irq startup 20 eth0: link up, 100Mbps, full-duplex, lpa 0x45E1 Please press Enter to activate this console. starting pid 812, tty '': '-/bin/sh' Loongson2@[\w]> you see vc_resize:814 resize_screen=80465504,new_cols=100,new_rows=37,err=0 so boot ok. Then see 2.6.27.7's vgacon_resize: 1279 static int vgacon_resize(struct vc_data *c, unsigned int width, 1280 unsigned int height, unsigned int user) 1281 { 1282 if (width % 2 || width > screen_info.orig_video_cols || 1283 height > (screen_info.orig_video_lines * vga_default_font_height)/ 1284 c->vc_font.height) 1285 /* let svgatextmode tinker with video timings and 1286 return success */ 1287 return (user) ? 0 : -EINVAL; 1288 1289 if (CON_IS_VISIBLE(c) && !vga_is_gfx) /* who knows */ 1290 vgacon_doresize(c, width, height); 1291 return 0; 1292 } Then see 2.6.18.1's vgacon_resize: 1266 static int vgacon_resize(struct vc_data *c, unsigned int width, 1267 unsigned int height) 1268 { 1269 if (width % 2 || width > ORIG_VIDEO_COLS || 1270 height > (ORIG_VIDEO_LINES * vga_default_font_height)/ 1271 c->vc_font.height) 1272 /* let svgatextmode tinker with video timings */ 1273 return 0; 1274 1275 if (CON_IS_VISIBLE(c) && !vga_is_gfx) /* who knows */ 1276 vgacon_doresize(c, width, height); 1277 return 0; 1278 } always return 0. My vga size's size is here on plat_mem_setup: 106 #ifdef CONFIG_VT 107 #if defined(CONFIG_VGA_CONSOLE) 108 conswitchp = &vga_con; 109 110 screen_info = (struct screen_info) { 111 0, 25, /* orig-x, orig-y */ 112 0, /* unused */ 113 0, /* orig-video-page */ 114 0, /* orig-video-mode */ 115 80, /* orig-video-cols */ 116 0, 0, 0, /* ega_ax, ega_bx, ega_cx */ 117 25, /* orig-video-lines */ 118 VIDEO_TYPE_VGAC, /* orig-video-isVGA */ 119 16 /* orig-video-points */ 120 }; 121 #elif defined(CONFIG_DUMMY_CONSOLE) 122 conswitchp = &dummy_con; 123 #endif 124 #endif So My coclusion: vgacon_resize return !0 cause vc_do_resize is delayed until on visual_init,on there vc->vc_origin has been changed to vc->vc_screenbuf ,but vc->vc_scr_end is not changed,and for vgacon vc->vc_scr_end is not related to vc->vc_screenbuf,which cause kernel die when copy old console data from vc->vc_origin till vc->vc_scr_end to new vc_origin. attachemt is vt.c on my test for 2.6.18 and 2.6.27. That's all,thanks! > thanks, > > greg k-h > >