Bug 15112

Summary:	Radeon KMS on RV250 gets wrong refresh rate.
Product:	Drivers	Reporter:	Joe Kowalski (joekowalski)
Component:	Video(DRI - non Intel)	Assignee:	drivers_video-dri
Status:	RESOLVED OBSOLETE
Severity:	normal	CC:	alexdeucher, joekowalski
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	2.6.33	Subsystem:
Regression:	No	Bisected commit-id:
Attachments:	Dmesg under Ums Dmesg under kms Xorg.0.log under ums Xorg.0.log under kms RV250 bios

Description Joe Kowalski 2010-01-23 07:57:32 UTC

When booting with KMS disabled, the ati UMS xorg driver properly sets the display mode to 1400x1050@60.2hz. xrandr reports the following modes:
$ DISPLAY=:0 xrandr
Screen 0: minimum 320 x 200, current 1400 x 1050, maximum 1400 x 1400
VGA-0 disconnected (normal left inverted right x axis y axis)        
LVDS connected 1400x1050+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1400x1050      60.2*+                                                         
   1280x1024      59.9     60.0                                                  
   1280x960       60.0     59.9                                                  
   1280x854       59.9                                                           
   1280x800       59.8                                                           
   1280x720       59.9                                                           
   1152x768       59.8                                                           
   1024x768       60.0     59.9                                                  
   800x600        60.3     59.9                                                  
   640x480        59.9     59.4                                                  
S-video disconnected (normal left inverted right x axis y axis)

However when booting with KMS enabled, all that appears is a black screen. After verifying that fbcon is built into the kernel and that KMS is initializing, I also found that the xserver had started up, but still with a blank screen. After blindly logging in, I ssh'd into the box, and found the following xrandr modes: 
$ DISPLAY=:0 xrandr
Screen 0: minimum 320 x 200, current 1400 x 1050, maximum 4096 x 4096
VGA-0 disconnected (normal left inverted right x axis y axis)
LVDS connected 1400x1050+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1400x1050      60.5 +   60.0*
   1280x1024      59.9     60.0
   1280x960       60.0     59.9
   1280x854       59.9
   1280x800       59.8
   1280x720       59.9
   1152x768       59.8
   1024x768       60.0     59.9
   800x600        60.3     59.9
   848x480        59.7
   720x480        59.7
   640x480        59.9     59.4
S-video disconnected (normal left inverted right x axis y axis)

It appears when using KMS, the correct refresh rate for the 1400x1050 resolution  isn't found and instead is a rate that doesn't work with this panel gets setup, resulting in a blank screen.

Comment 1 Joe Kowalski 2010-01-23 07:58:51 UTC

Created attachment 24680 [details]
Dmesg under Ums

Comment 2 Joe Kowalski 2010-01-23 08:06:29 UTC

Created attachment 24681 [details]
Dmesg under kms

Comment 3 Joe Kowalski 2010-01-23 08:07:37 UTC

Oops first attachment is under ums.

Comment 4 Joe Kowalski 2010-01-23 08:08:49 UTC

Created attachment 24682 [details]
Xorg.0.log under ums

Comment 5 Joe Kowalski 2010-01-23 08:09:22 UTC

Created attachment 24683 [details]
Xorg.0.log under kms

Comment 6 Joe Kowalski 2010-01-23 08:13:14 UTC

Forgot to add: Switching modes under kms with xrandr to a resolution below 1400x1050 results in a working display, although at a poorer resolution. Switching back to the 1400x1050 mode results in a black screen again.

Comment 7 Alex Deucher 2010-01-23 15:58:12 UTC

Under KMS you have two 1400x1050 modes:
LVDS connected 1400x1050+0+0 (normal left inverted right x axis y axis) 0mm x
0mm
   1400x1050      60.5 +   60.0*

For some reason, 1400x1050@60 is being selected (marked with the *) while 1400x1050@60.5 is the panel's preferred mode (marked with the +).  Does selecting 1400x1050@60.5 with xrandr work?  e.g.,
xrandr --output LVDS --mode 1400x1050 --rate 60.5

Comment 8 Joe Kowalski 2010-01-23 22:06:18 UTC

Okay, after boot it does default to the 60.5 rate, but only displaying the black screen:
$DISPLAY=:0 xrandr                                   
Screen 0: minimum 320 x 200, current 1400 x 1050, maximum 4096 x 4096         
VGA-0 disconnected (normal left inverted right x axis y axis)                 
LVDS connected 1400x1050+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1400x1050      60.5*+   60.0                                                  
   1280x1024      59.9     60.0                                                  
   1280x960       60.0     59.9                                                  
   1280x854       59.9                                                           
   1280x800       59.8                                                           
   1280x720       59.9                                                           
   1152x768       59.8                                                           
   1024x768       60.0     59.9                                                  
   800x600        60.3     59.9                                                  
   848x480        59.7                                                           
   720x480        59.7                                                           
   640x480        59.9     59.4                                                  
S-video disconnected (normal left inverted right x axis y axis)         

After switching to a different resolution or to the 60.0 rate (still a black screen), I can't switch back to the 60.5 rate:
$ DISPLAY=:0 xrandr -s 1400x1050 --rate 60.5     
$ DISPLAY=:0 xrandr 
Screen 0: minimum 320 x 200, current 1400 x 1050, maximum 4096 x 4096
VGA-0 disconnected (normal left inverted right x axis y axis)        
LVDS connected 1400x1050+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1400x1050      60.5 +   60.0*                                                 
   1280x1024      59.9     60.0                                                  
   1280x960       60.0     59.9                                                  
   1280x854       59.9                                                           
   1280x800       59.8                                                           
   1280x720       59.9                                                           
   1152x768       59.8                                                           
   1024x768       60.0     59.9                                                  
   800x600        60.3     59.9                                                  
   848x480        59.7                                                           
   720x480        59.7                                                           
   640x480        59.9     59.4                                                  
S-video disconnected (normal left inverted right x axis y axis)

Comment 9 Alex Deucher 2010-01-25 03:36:00 UTC

Can you attach a copy of your video bios?
as root:
cd /sys/bus/pci/devices/<pci bus id>
echo 1 > rom
cat rom > /tmp/rv250.rom
echo 0 > rom

Comment 10 Joe Kowalski 2010-01-25 05:50:07 UTC

Created attachment 24699 [details]
RV250 bios

Here you go.

Comment 11 Joe Kowalski 2010-02-27 16:14:55 UTC

This problem is still present in 2.6.33 final.

Comment 12 Joe Kowalski 2010-04-08 01:05:53 UTC

Still present with 2.6.34-rc+ at about 0fdf86754f70e813845af4abaa805165ce57a0bb.

Comment 13 Joe Kowalski 2011-03-29 16:00:40 UTC

Finally got around to upgrading that machine to 2.6.38, and KMS now sets a proper mode.