Bug 13419

Summary:	gspca: /dev/video0 changes to /dev/video1 after suspend
Product:	v4l-dvb	Reporter:	Márton Németh (nm127)
Component:	webcam	Assignee:	webcam (v4l-dvb_webcam)
Status:	CLOSED OBSOLETE
Severity:	normal	CC:	alan, moinejf
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	2.6.30-rc7	Subsystem:
Regression:	No	Bisected commit-id:
Attachments:	dmesg of 2.6.30-rc7 .config 2.6.30-rc7 on EeePC 901 dmesg, gspca_main loaded with parameter "debug=0x107" 2.6.30-rc7 kernel config with CONFIG_PM_DEBUG=y

Description Márton Németh 2009-06-01 05:59:47 UTC

Created attachment 21677 [details]
dmesg of 2.6.30-rc7

The gspca_sunplus driver with "Trust 610 LCD POWERC@M ZOOM" USB webcam (06d6:0031) does not work correctly in case of suspend/resume cycle. When the webcam picutre is shown on the screen while going to suspend then the original /dev/video0 device changes to /dev/video1.

Steps to reproduce:
1. Download and compile libv4l from http://people.atrpms.net/~hdegoede/libv4l-0.5.8.tar.gz
2. Download and compile "Simple V4L2 video viewer" from http://moinejf.free.fr/svv.c
3. Reboot the system
4. Plug in the "Trust 610 LCD POWERC@M ZOOM" device in webcam mode: the device will be recognised and the /dev/video0 device appears
5. Start svv (you might need to set LD_LIBRARY_PATH to point to libv4lconvert): the webcam picture is shown correctly
6. Suspend the machine. Make sure that svv is still running and shows the webcam picture.
7. Resume the machine

Current result:
 - The svv stops showing the webcam picture and exits
 - The /dev/video0 device disappears and /dev/video1 device appears
 - The following types of error messages appears on dmesg:

[   63.009860] [ INFO: possible circular locking dependency detected ]

[  100.021056] Restarting tasks ... <3>slab error in verify_redzone_free(): cache `size-1024': double free detected

[  100.241200] BUG: unable to handle kernel paging request at 6b6b6b6b

See the attached dmesg for details.

Comment 1 Márton Németh 2009-06-01 06:00:46 UTC

Created attachment 21678 [details]
.config 2.6.30-rc7 on EeePC 901

Comment 2 Márton Németh 2009-06-01 06:04:32 UTC

The "INFO: possible circular locking dependency detected" error message appears right after the svv was started. No suspend is needed to reproduce this message.

Comment 3 Márton Németh 2009-06-01 06:31:43 UTC

Created attachment 21679 [details]
dmesg, gspca_main loaded with parameter "debug=0x107"

I loaded gspca_main with debug outputs:

1. Reboot the system
2. modprobe -k gspca_main debug=0x107
3. Plug in the "Trust 610 LCD POWERC@M ZOOM" device in webcam mode
4. Start svv
5. Suspend the machine.
6. Resume the machine

Comment 4 Márton Németh 2009-06-01 16:05:11 UTC

Created attachment 21692 [details]
2.6.30-rc7 kernel config with CONFIG_PM_DEBUG=y

I compiled the kernel with CONFIG_PM_DEBUG=y and did some testing with the /sys/power/pm_test settings:

/sys/power/pm_test | result
-------------------+-----------------------------------
freezer            | works
devices            | works
platform           | works
processors         | works
core               | works
none               | does not work as described before