Bug 76998

Summary: hang on CEDAR right after log on
Product: DRI Reporter: tcl_de
Component: DRM/RadeonAssignee: Default DRI bug account <dri-devel>
Status: RESOLVED FIXED QA Contact:
Severity: critical    
Priority: medium    
Version: unspecified   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
Xorg log
none
dmesg
none
possible fix none

Description tcl_de 2014-04-03 12:25:24 UTC 
Using recent kernel versions, my Debian testing machine always hangs after the graphical log in. The X server and lightdm start normally but a few seconds after entering the credentials and pressing log in, the machine hangs. 

Kernel 3.8.1 works perfectly, but the Debian 3.11-2-amd64, 3.12-1-amd64 and 3.13-1-amd64 kernels don't.

In order to ensure that nothing has gone wrong with my installation, I also tried the openSUSE 13.1 KDE Live DVD but it also hangs shortly after the desktop has fully loaded.

My graphics card is a Radeon HD5450 (CEDAR).
Comment 1 Alex Deucher 2014-04-03 20:04:24 UTC 
please attach your xorg log and dmesg output.  Can you use git to bisect the kernel and find out what commit caused the regression?
Comment 2 tcl_de 2014-04-04 11:43:00 UTC 
Created attachment 96897 [details]
Xorg log
Comment 3 tcl_de 2014-04-04 11:51:19 UTC 
Created attachment 96898 [details]
dmesg
Comment 4 tcl_de 2014-04-04 11:59:52 UTC 
I did a small "bisection" and installed the 3.9.0-030900-generic, 3.10.0-031000-generic and 3.14.0-031400-generic kernels from the Ubuntu MainlineBuilds.

3.9 works, 3.10 and 3.14 hang.

The attached logs are for the 3.9 kernel.

I'm sorry, I prefer not to do a git bisect because I can only spend a limited amount of time on this bug.
Comment 5 tcl_de 2014-06-27 09:50:52 UTC 
The result of the bisect is
d4788db30a1a66255b592dd12613dda80c1443f7 is the first bad commit
commit d4788db30a1a66255b592dd12613dda80c1443f7
Author: Alex Deucher
Date:   Thu Feb 28 14:40:09 2013 -0500

    drm/radeon/evergreen: add support for golden register init
    
    Signed-off-by: Alex Deucher
Comment 6 Alex Deucher 2014-07-01 15:12:30 UTC 
(In reply to comment #5)
> The result of the bisect is
> d4788db30a1a66255b592dd12613dda80c1443f7 is the first bad commit
> commit d4788db30a1a66255b592dd12613dda80c1443f7
> Author: Alex Deucher
> Date:   Thu Feb 28 14:40:09 2013 -0500
> 
>     drm/radeon/evergreen: add support for golden register init
>     
>     Signed-off-by: Alex Deucher

Do you think you could go through the golden register arrays for cedar and narrow down which register(s) are problematic?
Comment 7 tcl_de 2014-07-06 21:11:54 UTC 
Yes, I think I can.
 
In fact, I already tried and managed to go through the register arrays. 
There is a single problematic register in cedar_golden_registers, namely 0x5cc. The complete corresponding row of the array is 0x5cc, 0xffffffff, 0x00000001 (line 384).
Comment 8 Alex Deucher 2014-07-07 22:03:48 UTC 
Created attachment 102392 [details] [review]
possible fix

The attached patch should fix the issue.
Comment 9 tcl_de 2014-07-13 11:11:51 UTC 
I can confirm that this patch fixes the issue.
Comment 10 tcl_de 2014-07-23 06:44:54 UTC 
I am closing this bug as the fix has landed in kernels 3.16-rc5, 3.15.6, 3.14.13, 3.12.25 and 3.10.49 .

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