Re: [PATCH 10/13] drm/xe/ttm: Reject VRAM allocations on wedged devices

["Yadav, Arvind" <arvind.yadav@intel.com>]

On 01-09-2026 02:33, Rodrigo Vivi wrote:
> On Thu, Aug 27, 2026 at 03:47:58PM +0530, Arvind Yadav wrote:
>> VRAM is no longer usable after the device is wedged. Reject new VRAM
>> allocations with -ENOSPC so TTM can try another placement, such as TT.
>>
>> An allocation racing with the wedge may still complete. The wedged fault
>> path prevents new VRAM CPU mappings, and device teardown releases the
>> resource.
>>
>> Cc: Matthew Brost <matthew.brost@intel.com>
>> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
>> Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
>> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
>> Assisted-by: Claude:claude-opus-4-8
>> Signed-off-by: Arvind Yadav <arvind.yadav@intel.com>
>> ---
>>   drivers/gpu/drm/xe/xe_ttm_vram_mgr.c | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
>> index 05911904c1f9..d0b266672010 100644
>> --- a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
>> +++ b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
>> @@ -54,6 +54,7 @@ static int xe_ttm_vram_mgr_new(struct ttm_resource_manager *man,
>>   			       const struct ttm_place *place,
>>   			       struct ttm_resource **res)
>>   {
>> +	struct xe_device *xe = ttm_to_xe_device(tbo->bdev);
>>   	struct xe_ttm_vram_mgr *mgr = to_xe_ttm_vram_mgr(man);
>>   	struct xe_ttm_vram_mgr_resource *vres;
>>   	struct gpu_buddy *mm = &mgr->mm;
>> @@ -61,6 +62,9 @@ static int xe_ttm_vram_mgr_new(struct ttm_resource_manager *man,
>>   	unsigned long lpfn;
>>   	int err;
>>   
>> +	if (xe_device_wedged(xe))
>> +		return -ENOSPC;
> is -ENOSPC the right return here? -EIO? -ENOENT? -ENODEV? -ENXIO? -EPIPE?


Thanks for the review.
I used -ENOSPC so TTM could try another placement such as TT.
I guess there is no need to try another placement after a permanent 
wedge because the device cannot process new work.

I will change it to -ENODEV so TTM returns a terminal error.

Thanks,
Arvind

>
>> +
>>   	lpfn = place->lpfn;
>>   	if (!lpfn || lpfn > man->size >> PAGE_SHIFT)
>>   		lpfn = man->size >> PAGE_SHIFT;
>> -- 
>> 2.43.0
>>