Long radeon stalls on recent kernels

[Andy Lutomirski]

On Tue, Dec 9, 2014 at 8:06 AM, Andy Lutomirski <luto at amacapital.net> wrote:
> On Tue, Dec 9, 2014 at 1:18 AM, Michel Dänzer <michel at daenzer.net> wrote:
>> On 09.12.2014 09:24, Andy Lutomirski wrote:
>>>
>>> The relevant line from latencytop seems to be:
>>>
>>> 154 20441402 489139 radeon_fence_default_wait [radeon]
>>> fence_wait_timeout ttm_bo_wait [ttm] ttm_bo_move_accel_cleanup [ttm]
>>> radeon_move_blit.isra.12 [radeon] radeon_bo_move [radeon]
>>> ttm_bo_handle_move_mem [ttm] ttm_bo_evict [ttm] ttm_mem_evict_first
>>> [ttm] ttm_bo_mem_space [ttm] ttm_bo_validate [ttm]
>>> radeon_bo_fault_reserve_notify [radeon]
>>
>> Which process is this?
>
> Xorg
>
>>
>> Looks like CPU access to a BO in VRAM, but the BO is located outside of
>> the CPU visible area of VRAM, so it has to be moved into the CPU visible
>> area first.
>>
>> Which version of Mesa are you using?
>>
>
> mesa-dri-drivers-10.3.3-1.20141110.fc20.x86_64
>
> I'm planning on upgrading to Fedora 21 fairly soon.

Upgrading to mesa-dri-drivers-10.3.3-1.20141110.fc21.x86_64 seems to
have helped enough that my usual test (open a couple of Firefox tabs
with graphics in them) doesn't hang anymore.

This card still isn't *fast*.  Is there some way I can check that I'm
actually using all 16 PCIe lanes?  In my tinkering w/ power management
settings, I got some odd logs suggesting that only one lane was in
use.

Other than that, maybe everything works :)  But I'm still waiting for
the day that buggy userspace *can't* cause kernel graphics stalls.

--Andy

>
> --Andy
>
>>
>> --
>> Earthling Michel Dänzer               |               http://www.amd.com
>> Libre software enthusiast             |             Mesa and X developer
>
>
>
> --
> Andy Lutomirski
> AMA Capital Management, LLC



-- 
Andy Lutomirski
AMA Capital Management, LLC