[PATCH] drm/radeon: fix VM page table setup on SI

[Jerome Glisse]

On Fri, Jun 29, 2012 at 11:23 AM, Alex Deucher <alexdeucher at gmail.com> wrote:
> On Fri, Jun 29, 2012 at 10:49 AM, Michel Dänzer <michel at daenzer.net> wrote:
>> On Don, 2012-06-28 at 17:53 -0400, alexdeucher at gmail.com wrote:
>>> From: Alex Deucher <alexander.deucher at amd.com>
>>>
>>> Cayman and trinity allow for variable sized VM page
>>> tables, but SI requires that all page tables be the
>>> same size.  The current code assumes variablely sized
>>> VM page tables so SI may end up with part of each page
>>> table overlapping with other memory which could end
>>> up being interpreted by the VM hw as garbage.
>>>
>>> Change the code to better accomodate SI.  Allocate enough
>>> space for at least 2 full page tables and always set
>>> last_pfn to max_pfn on SI so each VM is backed by a full
>>> page table.  This limits us to only 2 VMs active at any
>>> given time on SI.  This will be rectified and the code can
>>> be reunified once we move to two level page tables.
>>>
>>> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
>>
>> This change breaks the radeonsi driver for me. egltri_screen (the
>> 'golden' test for radeonsi at least basically working) locks up the
>> GPU.
>>
>> I don't have any details about the lockup yet, as the GPU reset attempt
>> hangs the machine. Any ideas offhand what radeonsi might be doing wrong?
>
> Maybe trying to access an unmapped page that happened to work by
> accident before and now causes a fault in the VM which halts the MC?
>
> Alex
>

Yeah only thing i can think of, can you get dump of various mc fault
reg after lockup ?

Cheers,
Jerome