[Intel-gfx] [PATCH 0/8] Convert the intel iommu driver to the dma-iommu api

[Tvrtko Ursulin]

On 08/09/2020 16:44, Logan Gunthorpe wrote:
> On 2020-09-08 9:28 a.m., Tvrtko Ursulin wrote:
>>>
>>> diff --git a/drivers/gpu/drm/i915/i915_scatterlist.h
>>> b/drivers/gpu/drm/i915/i915
>>> index b7b59328cb76..9367ac801f0c 100644
>>> --- a/drivers/gpu/drm/i915/i915_scatterlist.h
>>> +++ b/drivers/gpu/drm/i915/i915_scatterlist.h
>>> @@ -27,13 +27,19 @@ static __always_inline struct sgt_iter {
>>>    } __sgt_iter(struct scatterlist *sgl, bool dma) {
>>>           struct sgt_iter s = { .sgp = sgl };
>>>
>>> +       if (sgl && !sg_dma_len(s.sgp))
>>
>> I'd extend the condition to be, just to be safe:
>>      if (dma && sgl && !sg_dma_len(s.sgp))
>>
> 
> Right, good catch, that's definitely necessary.
> 
>>> +               s.sgp = NULL;
>>> +
>>>           if (s.sgp) {
>>>                   s.max = s.curr = s.sgp->offset;
>>> -               s.max += s.sgp->length;
>>> -               if (dma)
>>> +
>>> +               if (dma) {
>>> +                       s.max += sg_dma_len(s.sgp);
>>>                           s.dma = sg_dma_address(s.sgp);
>>> -               else
>>> +               } else {
>>> +                       s.max += s.sgp->length;
>>>                           s.pfn = page_to_pfn(sg_page(s.sgp));
>>> +               }
>>
>> Otherwise has this been tested or alternatively how to test it? (How to
>> repro the issue.)
> 
> It has not been tested. To test it, you need Tom's patch set without the
> last "DO NOT MERGE" patch:
> 
> https://lkml.kernel.org/lkml/20200907070035.GA25114@infradead.org/T/

Tom, do you have a branch somewhere I could pull from? (Just being lazy 
about downloading a bunch of messages from the archives.)

What GPU is in your Lenovo x1 carbon 5th generation and what 
graphical/desktop setup I need to repro?

Regards,

Tvrtko