On Tue, 8 Sep 2020 at 16:56, Tvrtko Ursulin
<[email protected]> wrote:
>
>
> 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/[email protected]/T/
>
> Tom, do you have a branch somewhere I could pull from? (Just being lazy
> about downloading a bunch of messages from the archives.)
I don't unfortunately. I'm working locally with poor internet.
>
> What GPU is in your Lenovo x1 carbon 5th generation and what
> graphical/desktop setup I need to repro?
Is this enough info?:
$ lspci -vnn | grep VGA -A 12
00:02.0 VGA compatible controller [0300]: Intel Corporation HD
Graphics 620 [8086:5916] (rev 02) (prog-if 00 [VGA controller])
Subsystem: Lenovo ThinkPad X1 Carbon 5th Gen [17aa:224f]
Flags: bus master, fast devsel, latency 0, IRQ 148
Memory at eb000000 (64-bit, non-prefetchable) [size=16M]
Memory at 60000000 (64-bit, prefetchable) [size=256M]
I/O ports at e000 [size=64]
[virtual] Expansion ROM at 000c0000 [disabled] [size=128K]
Capabilities: [40] Vendor Specific Information: Len=0c <?>
Capabilities: [70] Express Root Complex Integrated Endpoint, MSI 00
Capabilities: [ac] MSI: Enable+ Count=1/1 Maskable- 64bit-
Capabilities: [d0] Power Management version 2
Capabilities: [100] Process Address Space ID (PASID)
Capabilities: [200] Address Translation Service (ATS)
>
> Regards,
>
> Tvrtko
On 08/09/2020 23:43, Tom Murphy wrote:
> On Tue, 8 Sep 2020 at 16:56, Tvrtko Ursulin
> <[email protected]> wrote:
>>
>>
>> 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/[email protected]/T/
>>
>> Tom, do you have a branch somewhere I could pull from? (Just being lazy
>> about downloading a bunch of messages from the archives.)
>
> I don't unfortunately. I'm working locally with poor internet.
>
>>
>> What GPU is in your Lenovo x1 carbon 5th generation and what
>> graphical/desktop setup I need to repro?
>
>
> Is this enough info?:
>
> $ lspci -vnn | grep VGA -A 12
> 00:02.0 VGA compatible controller [0300]: Intel Corporation HD
> Graphics 620 [8086:5916] (rev 02) (prog-if 00 [VGA controller])
> Subsystem: Lenovo ThinkPad X1 Carbon 5th Gen [17aa:224f]
> Flags: bus master, fast devsel, latency 0, IRQ 148
> Memory at eb000000 (64-bit, non-prefetchable) [size=16M]
> Memory at 60000000 (64-bit, prefetchable) [size=256M]
> I/O ports at e000 [size=64]
> [virtual] Expansion ROM at 000c0000 [disabled] [size=128K]
> Capabilities: [40] Vendor Specific Information: Len=0c <?>
> Capabilities: [70] Express Root Complex Integrated Endpoint, MSI 00
> Capabilities: [ac] MSI: Enable+ Count=1/1 Maskable- 64bit-
> Capabilities: [d0] Power Management version 2
> Capabilities: [100] Process Address Space ID (PASID)
> Capabilities: [200] Address Translation Service (ATS)
Works for a start. What about the steps to repro? Any desktop
environment and it is just visual corruption, no hangs/stalls or such?
I've submitted a series consisting of what I understood are the patches
needed to repro the issue to our automated CI here:
https://patchwork.freedesktop.org/series/81489/
So will see if it will catch something, or more targeted testing will be
required. Hopefully it does trip over in which case I can add the patch
suggested by Logan on top and see if that fixes it. Or I'll need to
write a new test case.
If you could glance over my series to check I identified the patches
correctly it would be appreciated.
Regards,
Tvrtko