Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Bjorn Helgaas]

[+cc Sasha -- stable kernel regression]
[+cc Patrick, Kai-Heng, LKML]

On Fri, Jul 17, 2020 at 12:10:39AM +0200, Karol Herbst wrote:
> On Tue, Jul 7, 2020 at 9:30 PM Karol Herbst <kherbst@redhat.com> wrote:
> >
> > Hi everybody,
> >
> > with the mentioned commit Nouveau isn't able to load firmware onto the
> > GPU on one of my systems here. Even though the issue doesn't always
> > happen I am quite confident this is the commit breaking it.
> >
> > I am still digging into the issue and trying to figure out what
> > exactly breaks, but it shows up in different ways. Either we are not
> > able to boot the engines on the GPU or the GPU becomes unresponsive.
> > Btw, this is also a system where our runtime power management issue
> > shows up, so maybe there is indeed something funky with the bridge
> > controller.
> >
> > Just pinging you in case you have an idea on how this could break Nouveau
> >
> > most of the times it shows up like this:
> > nouveau 0000:01:00.0: acr: AHESASC binary failed
> >
> > Sometimes it works at boot and fails at runtime resuming with random
> > faults. So I will be investigating a bit more, but yeah... I am super
> > sure the commit triggered this issue, no idea if it actually causes
> > it.
> 
> so yeah.. I reverted that locally and never ran into issues again.
> Still valid on latest 5.7. So can we get this reverted or properly
> fixed? This breaks runtime pm for us on at least some hardware.

Yeah, that stinks.  We had another similar report from Patrick:

  https://lore.kernel.org/r/CAErSpo5sTeK_my1dEhWp7aHD0xOp87+oHYWkTjbL7ALgDbXo-Q@mail.gmail.com

Apparently the problem is ec411e02b7a2 ("PCI/PM: Assume ports without
DLL Link Active train links in 100 ms"), which Patrick found was
backported to v5.4.49 as 828b192c57e8, and you found was backported to
v5.7.6 as afaff825e3a4.

Oddly, Patrick reported that v5.7.7 worked correctly, even though it
still contains afaff825e3a4.

I guess in the absence of any other clues we'll have to revert it.
I hate to do that because that means we'll have slow resume of
Thunderbolt-connected devices again, but that's better than having
GPUs completely broken.

Could you and Patrick open bugzilla.kernel.org reports, attach dmesg
logs and "sudo lspci -vv" output, and add the URLs to Kai-Heng's
original report at https://bugzilla.kernel.org/show_bug.cgi?id=206837
and to this thread?

There must be a way to fix the slow resume problem without breaking
the GPUs.

Bjorn

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Karol Herbst]

On Fri, Jul 17, 2020 at 1:54 AM Bjorn Helgaas <helgaas@kernel.org> wrote:
>
> [+cc Sasha -- stable kernel regression]
> [+cc Patrick, Kai-Heng, LKML]
>
> On Fri, Jul 17, 2020 at 12:10:39AM +0200, Karol Herbst wrote:
> > On Tue, Jul 7, 2020 at 9:30 PM Karol Herbst <kherbst@redhat.com> wrote:
> > >
> > > Hi everybody,
> > >
> > > with the mentioned commit Nouveau isn't able to load firmware onto the
> > > GPU on one of my systems here. Even though the issue doesn't always
> > > happen I am quite confident this is the commit breaking it.
> > >
> > > I am still digging into the issue and trying to figure out what
> > > exactly breaks, but it shows up in different ways. Either we are not
> > > able to boot the engines on the GPU or the GPU becomes unresponsive.
> > > Btw, this is also a system where our runtime power management issue
> > > shows up, so maybe there is indeed something funky with the bridge
> > > controller.
> > >
> > > Just pinging you in case you have an idea on how this could break Nouveau
> > >
> > > most of the times it shows up like this:
> > > nouveau 0000:01:00.0: acr: AHESASC binary failed
> > >
> > > Sometimes it works at boot and fails at runtime resuming with random
> > > faults. So I will be investigating a bit more, but yeah... I am super
> > > sure the commit triggered this issue, no idea if it actually causes
> > > it.
> >
> > so yeah.. I reverted that locally and never ran into issues again.
> > Still valid on latest 5.7. So can we get this reverted or properly
> > fixed? This breaks runtime pm for us on at least some hardware.
>
> Yeah, that stinks.  We had another similar report from Patrick:
>
>   https://lore.kernel.org/r/CAErSpo5sTeK_my1dEhWp7aHD0xOp87+oHYWkTjbL7ALgDbXo-Q@mail.gmail.com
>
> Apparently the problem is ec411e02b7a2 ("PCI/PM: Assume ports without
> DLL Link Active train links in 100 ms"), which Patrick found was
> backported to v5.4.49 as 828b192c57e8, and you found was backported to
> v5.7.6 as afaff825e3a4.
>
> Oddly, Patrick reported that v5.7.7 worked correctly, even though it
> still contains afaff825e3a4.
>
> I guess in the absence of any other clues we'll have to revert it.
> I hate to do that because that means we'll have slow resume of
> Thunderbolt-connected devices again, but that's better than having
> GPUs completely broken.
>
> Could you and Patrick open bugzilla.kernel.org reports, attach dmesg
> logs and "sudo lspci -vv" output, and add the URLs to Kai-Heng's
> original report at https://bugzilla.kernel.org/show_bug.cgi?id=206837
> and to this thread?
>
> There must be a way to fix the slow resume problem without breaking
> the GPUs.
>

I wouldn't be surprised if this is related to the Intel bridge we
check against for Nouveau.. I still have to check on another laptop
with the same bridge our workaround was required as well but wouldn't
be surprised if it shows the same problem. Will get you the
information from both systems tomorrow then.

> Bjorn
>

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Karol Herbst]

Filed at https://bugzilla.kernel.org/show_bug.cgi?id=208597

oddly enough I wasn't able to reproduce it on my XPS 9560, will ping
once something breaks.

On Fri, Jul 17, 2020 at 2:43 AM Karol Herbst <kherbst@redhat.com> wrote:
>
> On Fri, Jul 17, 2020 at 1:54 AM Bjorn Helgaas <helgaas@kernel.org> wrote:
> >
> > [+cc Sasha -- stable kernel regression]
> > [+cc Patrick, Kai-Heng, LKML]
> >
> > On Fri, Jul 17, 2020 at 12:10:39AM +0200, Karol Herbst wrote:
> > > On Tue, Jul 7, 2020 at 9:30 PM Karol Herbst <kherbst@redhat.com> wrote:
> > > >
> > > > Hi everybody,
> > > >
> > > > with the mentioned commit Nouveau isn't able to load firmware onto the
> > > > GPU on one of my systems here. Even though the issue doesn't always
> > > > happen I am quite confident this is the commit breaking it.
> > > >
> > > > I am still digging into the issue and trying to figure out what
> > > > exactly breaks, but it shows up in different ways. Either we are not
> > > > able to boot the engines on the GPU or the GPU becomes unresponsive.
> > > > Btw, this is also a system where our runtime power management issue
> > > > shows up, so maybe there is indeed something funky with the bridge
> > > > controller.
> > > >
> > > > Just pinging you in case you have an idea on how this could break Nouveau
> > > >
> > > > most of the times it shows up like this:
> > > > nouveau 0000:01:00.0: acr: AHESASC binary failed
> > > >
> > > > Sometimes it works at boot and fails at runtime resuming with random
> > > > faults. So I will be investigating a bit more, but yeah... I am super
> > > > sure the commit triggered this issue, no idea if it actually causes
> > > > it.
> > >
> > > so yeah.. I reverted that locally and never ran into issues again.
> > > Still valid on latest 5.7. So can we get this reverted or properly
> > > fixed? This breaks runtime pm for us on at least some hardware.
> >
> > Yeah, that stinks.  We had another similar report from Patrick:
> >
> >   https://lore.kernel.org/r/CAErSpo5sTeK_my1dEhWp7aHD0xOp87+oHYWkTjbL7ALgDbXo-Q@mail.gmail.com
> >
> > Apparently the problem is ec411e02b7a2 ("PCI/PM: Assume ports without
> > DLL Link Active train links in 100 ms"), which Patrick found was
> > backported to v5.4.49 as 828b192c57e8, and you found was backported to
> > v5.7.6 as afaff825e3a4.
> >
> > Oddly, Patrick reported that v5.7.7 worked correctly, even though it
> > still contains afaff825e3a4.
> >
> > I guess in the absence of any other clues we'll have to revert it.
> > I hate to do that because that means we'll have slow resume of
> > Thunderbolt-connected devices again, but that's better than having
> > GPUs completely broken.
> >
> > Could you and Patrick open bugzilla.kernel.org reports, attach dmesg
> > logs and "sudo lspci -vv" output, and add the URLs to Kai-Heng's
> > original report at https://bugzilla.kernel.org/show_bug.cgi?id=206837
> > and to this thread?
> >
> > There must be a way to fix the slow resume problem without breaking
> > the GPUs.
> >
>
> I wouldn't be surprised if this is related to the Intel bridge we
> check against for Nouveau.. I still have to check on another laptop
> with the same bridge our workaround was required as well but wouldn't
> be surprised if it shows the same problem. Will get you the
> information from both systems tomorrow then.
>
> > Bjorn
> >

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Mika Westerberg]

Hi,

[Sorry for the delay, I was on vacation]

On Fri, Jul 17, 2020 at 01:32:10PM +0200, Karol Herbst wrote:
> Filed at https://bugzilla.kernel.org/show_bug.cgi?id=208597

Thanks for reporting.

I'll check your logs and try to figure if there is something we can do
to make both nouveau and TBT working at the same time.

> oddly enough I wasn't able to reproduce it on my XPS 9560, will ping
> once something breaks.

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Lyude Paul]

Sure thing. Also, feel free to let me know if you'd like access to one of the
systems we saw breaking with this patch - I'm fairly sure I've got one of them
locally at my apartment and don't mind setting up AMT/KVM/SSH

On Tue, 2020-07-21 at 15:22 +0300, Mika Westerberg wrote:
> Hi,
> 
> [Sorry for the delay, I was on vacation]
> 
> On Fri, Jul 17, 2020 at 01:32:10PM +0200, Karol Herbst wrote:
> > Filed at https://bugzilla.kernel.org/show_bug.cgi?id=208597
> 
> Thanks for reporting.
> 
> I'll check your logs and try to figure if there is something we can do
> to make both nouveau and TBT working at the same time.
> 
> > oddly enough I wasn't able to reproduce it on my XPS 9560, will ping
> > once something breaks.
-- 
Cheers,
	Lyude Paul (she/her)
	Software Engineer at Red Hat

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Mika Westerberg]

On Tue, Jul 21, 2020 at 11:01:55AM -0400, Lyude Paul wrote:
> Sure thing. Also, feel free to let me know if you'd like access to one of the
> systems we saw breaking with this patch - I'm fairly sure I've got one of them
> locally at my apartment and don't mind setting up AMT/KVM/SSH

Probably no need for remote access (thanks for the offer, though). I
attached a test patch to the bug report:

  https://bugzilla.kernel.org/show_bug.cgi?id=208597

that tries to work it around (based on the ->pm_cap == 0). I wonder if
anyone would have time to try it out.

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Lyude Paul]

On Tue, 2020-07-21 at 18:27 +0300, Mika Westerberg wrote:
> On Tue, Jul 21, 2020 at 11:01:55AM -0400, Lyude Paul wrote:
> > Sure thing. Also, feel free to let me know if you'd like access to one of
> > the
> > systems we saw breaking with this patch - I'm fairly sure I've got one of
> > them
> > locally at my apartment and don't mind setting up AMT/KVM/SSH
> 
> Probably no need for remote access (thanks for the offer, though). I
> attached a test patch to the bug report:
> 
>   https://bugzilla.kernel.org/show_bug.cgi?id=208597
> 
> that tries to work it around (based on the ->pm_cap == 0). I wonder if
> anyone would have time to try it out.

Will give it a shot today and let you know the result

> 
-- 
Cheers,
	Lyude Paul (she/her)
	Software Engineer at Red Hat

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Lyude Paul]

On Tue, 2020-07-21 at 12:00 -0400, Lyude Paul wrote:
> On Tue, 2020-07-21 at 18:27 +0300, Mika Westerberg wrote:
> > On Tue, Jul 21, 2020 at 11:01:55AM -0400, Lyude Paul wrote:
> > > Sure thing. Also, feel free to let me know if you'd like access to one
> > > of
> > > the
> > > systems we saw breaking with this patch - I'm fairly sure I've got one
> > > of
> > > them
> > > locally at my apartment and don't mind setting up AMT/KVM/SSH
> > 
> > Probably no need for remote access (thanks for the offer, though). I
> > attached a test patch to the bug report:
> > 
> >   https://bugzilla.kernel.org/show_bug.cgi?id=208597
> > 
> > that tries to work it around (based on the ->pm_cap == 0). I wonder if
> > anyone would have time to try it out.
> 
> Will give it a shot today and let you know the result

Ahh-actually, I thought the laptop I had locally could reproduce this bug but
that doesn't appear to be the case whoops. Karol Herbst still has access to a
machine that can test this though, so they'll likely get to trying the patch
today or tommorrow

> 
-- 
Cheers,
	Lyude Paul (she/her)
	Software Engineer at Red Hat

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Mika Westerberg]

On Tue, Jul 21, 2020 at 02:24:19PM -0400, Lyude Paul wrote:
> On Tue, 2020-07-21 at 12:00 -0400, Lyude Paul wrote:
> > On Tue, 2020-07-21 at 18:27 +0300, Mika Westerberg wrote:
> > > On Tue, Jul 21, 2020 at 11:01:55AM -0400, Lyude Paul wrote:
> > > > Sure thing. Also, feel free to let me know if you'd like access to one
> > > > of
> > > > the
> > > > systems we saw breaking with this patch - I'm fairly sure I've got one
> > > > of
> > > > them
> > > > locally at my apartment and don't mind setting up AMT/KVM/SSH
> > > 
> > > Probably no need for remote access (thanks for the offer, though). I
> > > attached a test patch to the bug report:
> > > 
> > >   https://bugzilla.kernel.org/show_bug.cgi?id=208597
> > > 
> > > that tries to work it around (based on the ->pm_cap == 0). I wonder if
> > > anyone would have time to try it out.
> > 
> > Will give it a shot today and let you know the result
> 
> Ahh-actually, I thought the laptop I had locally could reproduce this bug but
> that doesn't appear to be the case whoops. Karol Herbst still has access to a
> machine that can test this though, so they'll likely get to trying the patch
> today or tommorrow

OK sounds good :)

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Patrick Volkerding]

On 7/21/20 10:27 AM, Mika Westerberg wrote:
> On Tue, Jul 21, 2020 at 11:01:55AM -0400, Lyude Paul wrote:
>> Sure thing. Also, feel free to let me know if you'd like access to one of the
>> systems we saw breaking with this patch - I'm fairly sure I've got one of them
>> locally at my apartment and don't mind setting up AMT/KVM/SSH
> Probably no need for remote access (thanks for the offer, though). I
> attached a test patch to the bug report:
>
>   https://bugzilla.kernel.org/show_bug.cgi?id=208597
>
> that tries to work it around (based on the ->pm_cap == 0). I wonder if
> anyone would have time to try it out.


Hi Mika,

I can confirm that this patch applied to 5.4.52 fixes the issue with
hybrid graphics on the Thinkpad X1 Extreme gen2.

Thanks,

Pat

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Mika Westerberg]

On Tue, Jul 21, 2020 at 01:37:12PM -0500, Patrick Volkerding wrote:
> On 7/21/20 10:27 AM, Mika Westerberg wrote:
> > On Tue, Jul 21, 2020 at 11:01:55AM -0400, Lyude Paul wrote:
> >> Sure thing. Also, feel free to let me know if you'd like access to one of the
> >> systems we saw breaking with this patch - I'm fairly sure I've got one of them
> >> locally at my apartment and don't mind setting up AMT/KVM/SSH
> > Probably no need for remote access (thanks for the offer, though). I
> > attached a test patch to the bug report:
> >
> >   https://bugzilla.kernel.org/show_bug.cgi?id=208597
> >
> > that tries to work it around (based on the ->pm_cap == 0). I wonder if
> > anyone would have time to try it out.
> 
> 
> Hi Mika,
> 
> I can confirm that this patch applied to 5.4.52 fixes the issue with
> hybrid graphics on the Thinkpad X1 Extreme gen2.

Great, thanks for testing!

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Karol Herbst]

On Wed, Jul 22, 2020 at 11:25 AM Mika Westerberg
<mika.westerberg@linux.intel.com> wrote:
>
> On Tue, Jul 21, 2020 at 01:37:12PM -0500, Patrick Volkerding wrote:
> > On 7/21/20 10:27 AM, Mika Westerberg wrote:
> > > On Tue, Jul 21, 2020 at 11:01:55AM -0400, Lyude Paul wrote:
> > >> Sure thing. Also, feel free to let me know if you'd like access to one of the
> > >> systems we saw breaking with this patch - I'm fairly sure I've got one of them
> > >> locally at my apartment and don't mind setting up AMT/KVM/SSH
> > > Probably no need for remote access (thanks for the offer, though). I
> > > attached a test patch to the bug report:
> > >
> > >   https://bugzilla.kernel.org/show_bug.cgi?id=208597
> > >
> > > that tries to work it around (based on the ->pm_cap == 0). I wonder if
> > > anyone would have time to try it out.
> >
> >
> > Hi Mika,
> >
> > I can confirm that this patch applied to 5.4.52 fixes the issue with
> > hybrid graphics on the Thinkpad X1 Extreme gen2.
>
> Great, thanks for testing!
>

yeah, works on the P1G2 as well.

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Mika Westerberg]

On Thu, Jul 23, 2020 at 10:30:58PM +0200, Karol Herbst wrote:
> On Wed, Jul 22, 2020 at 11:25 AM Mika Westerberg
> <mika.westerberg@linux.intel.com> wrote:
> >
> > On Tue, Jul 21, 2020 at 01:37:12PM -0500, Patrick Volkerding wrote:
> > > On 7/21/20 10:27 AM, Mika Westerberg wrote:
> > > > On Tue, Jul 21, 2020 at 11:01:55AM -0400, Lyude Paul wrote:
> > > >> Sure thing. Also, feel free to let me know if you'd like access to one of the
> > > >> systems we saw breaking with this patch - I'm fairly sure I've got one of them
> > > >> locally at my apartment and don't mind setting up AMT/KVM/SSH
> > > > Probably no need for remote access (thanks for the offer, though). I
> > > > attached a test patch to the bug report:
> > > >
> > > >   https://bugzilla.kernel.org/show_bug.cgi?id=208597
> > > >
> > > > that tries to work it around (based on the ->pm_cap == 0). I wonder if
> > > > anyone would have time to try it out.
> > >
> > >
> > > Hi Mika,
> > >
> > > I can confirm that this patch applied to 5.4.52 fixes the issue with
> > > hybrid graphics on the Thinkpad X1 Extreme gen2.
> >
> > Great, thanks for testing!
> >
> 
> yeah, works on the P1G2 as well.

Thanks for testing!

Since we have the revert queued for this release cycle, I think I will
send an updated version of "PCI/PM: Assume ports without DLL Link Active
train links in 100 ms" after v5.9-rc1 is released that has this
workaround in place.

(I'm continuing my vacation so will be offline next week).

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Bjorn Helgaas]

On Fri, Jul 24, 2020 at 12:57:51PM +0300, Mika Westerberg wrote:
> On Thu, Jul 23, 2020 at 10:30:58PM +0200, Karol Herbst wrote:
> > On Wed, Jul 22, 2020 at 11:25 AM Mika Westerberg
> > <mika.westerberg@linux.intel.com> wrote:
> > >
> > > On Tue, Jul 21, 2020 at 01:37:12PM -0500, Patrick Volkerding wrote:
> > > > On 7/21/20 10:27 AM, Mika Westerberg wrote:
> > > > > On Tue, Jul 21, 2020 at 11:01:55AM -0400, Lyude Paul wrote:
> > > > >> Sure thing. Also, feel free to let me know if you'd like access to one of the
> > > > >> systems we saw breaking with this patch - I'm fairly sure I've got one of them
> > > > >> locally at my apartment and don't mind setting up AMT/KVM/SSH
> > > > > Probably no need for remote access (thanks for the offer, though). I
> > > > > attached a test patch to the bug report:
> > > > >
> > > > >   https://bugzilla.kernel.org/show_bug.cgi?id=208597
> > > > >
> > > > > that tries to work it around (based on the ->pm_cap == 0). I wonder if
> > > > > anyone would have time to try it out.
> > > >
> > > >
> > > > Hi Mika,
> > > >
> > > > I can confirm that this patch applied to 5.4.52 fixes the issue with
> > > > hybrid graphics on the Thinkpad X1 Extreme gen2.
> > >
> > > Great, thanks for testing!
> > 
> > yeah, works on the P1G2 as well.
> 
> Thanks for testing!
> 
> Since we have the revert queued for this release cycle, I think I will
> send an updated version of "PCI/PM: Assume ports without DLL Link Active
> train links in 100 ms" after v5.9-rc1 is released that has this
> workaround in place.
> 
> (I'm continuing my vacation so will be offline next week).

Sounds fine, sorry for interrupting your vacation!

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Sasha Levin]

On Fri, Jul 17, 2020 at 02:43:52AM +0200, Karol Herbst wrote:
>On Fri, Jul 17, 2020 at 1:54 AM Bjorn Helgaas <helgaas@kernel.org> wrote:
>>
>> [+cc Sasha -- stable kernel regression]
>> [+cc Patrick, Kai-Heng, LKML]
>>
>> On Fri, Jul 17, 2020 at 12:10:39AM +0200, Karol Herbst wrote:
>> > On Tue, Jul 7, 2020 at 9:30 PM Karol Herbst <kherbst@redhat.com> wrote:
>> > >
>> > > Hi everybody,
>> > >
>> > > with the mentioned commit Nouveau isn't able to load firmware onto the
>> > > GPU on one of my systems here. Even though the issue doesn't always
>> > > happen I am quite confident this is the commit breaking it.
>> > >
>> > > I am still digging into the issue and trying to figure out what
>> > > exactly breaks, but it shows up in different ways. Either we are not
>> > > able to boot the engines on the GPU or the GPU becomes unresponsive.
>> > > Btw, this is also a system where our runtime power management issue
>> > > shows up, so maybe there is indeed something funky with the bridge
>> > > controller.
>> > >
>> > > Just pinging you in case you have an idea on how this could break Nouveau
>> > >
>> > > most of the times it shows up like this:
>> > > nouveau 0000:01:00.0: acr: AHESASC binary failed
>> > >
>> > > Sometimes it works at boot and fails at runtime resuming with random
>> > > faults. So I will be investigating a bit more, but yeah... I am super
>> > > sure the commit triggered this issue, no idea if it actually causes
>> > > it.
>> >
>> > so yeah.. I reverted that locally and never ran into issues again.
>> > Still valid on latest 5.7. So can we get this reverted or properly
>> > fixed? This breaks runtime pm for us on at least some hardware.
>>
>> Yeah, that stinks.  We had another similar report from Patrick:
>>
>>   https://lore.kernel.org/r/CAErSpo5sTeK_my1dEhWp7aHD0xOp87+oHYWkTjbL7ALgDbXo-Q@mail.gmail.com
>>
>> Apparently the problem is ec411e02b7a2 ("PCI/PM: Assume ports without
>> DLL Link Active train links in 100 ms"), which Patrick found was
>> backported to v5.4.49 as 828b192c57e8, and you found was backported to
>> v5.7.6 as afaff825e3a4.
>>
>> Oddly, Patrick reported that v5.7.7 worked correctly, even though it
>> still contains afaff825e3a4.
>>
>> I guess in the absence of any other clues we'll have to revert it.
>> I hate to do that because that means we'll have slow resume of
>> Thunderbolt-connected devices again, but that's better than having
>> GPUs completely broken.
>>
>> Could you and Patrick open bugzilla.kernel.org reports, attach dmesg
>> logs and "sudo lspci -vv" output, and add the URLs to Kai-Heng's
>> original report at https://bugzilla.kernel.org/show_bug.cgi?id=206837
>> and to this thread?
>>
>> There must be a way to fix the slow resume problem without breaking
>> the GPUs.
>>
>
>I wouldn't be surprised if this is related to the Intel bridge we
>check against for Nouveau.. I still have to check on another laptop
>with the same bridge our workaround was required as well but wouldn't
>be surprised if it shows the same problem. Will get you the
>information from both systems tomorrow then.

I take it that ec411e02b7a2 will be reverted upstream?

-- 
Thanks,
Sasha

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Bjorn Helgaas]

On Fri, Jul 17, 2020 at 10:43:18AM -0400, Sasha Levin wrote:
> On Fri, Jul 17, 2020 at 02:43:52AM +0200, Karol Herbst wrote:
> > On Fri, Jul 17, 2020 at 1:54 AM Bjorn Helgaas <helgaas@kernel.org> wrote:
> > > On Fri, Jul 17, 2020 at 12:10:39AM +0200, Karol Herbst wrote:
> > > > On Tue, Jul 7, 2020 at 9:30 PM Karol Herbst <kherbst@redhat.com> wrote:
> > > > >
> > > > > Hi everybody,
> > > > >
> > > > > with the mentioned commit Nouveau isn't able to load firmware onto the
> > > > > GPU on one of my systems here. Even though the issue doesn't always
> > > > > happen I am quite confident this is the commit breaking it.
> > > > >
> > > > > I am still digging into the issue and trying to figure out what
> > > > > exactly breaks, but it shows up in different ways. Either we are not
> > > > > able to boot the engines on the GPU or the GPU becomes unresponsive.
> > > > > Btw, this is also a system where our runtime power management issue
> > > > > shows up, so maybe there is indeed something funky with the bridge
> > > > > controller.
> > > > >
> > > > > Just pinging you in case you have an idea on how this could break Nouveau
> > > > >
> > > > > most of the times it shows up like this:
> > > > > nouveau 0000:01:00.0: acr: AHESASC binary failed
> > > > >
> > > > > Sometimes it works at boot and fails at runtime resuming with random
> > > > > faults. So I will be investigating a bit more, but yeah... I am super
> > > > > sure the commit triggered this issue, no idea if it actually causes
> > > > > it.
> > > >
> > > > so yeah.. I reverted that locally and never ran into issues again.
> > > > Still valid on latest 5.7. So can we get this reverted or properly
> > > > fixed? This breaks runtime pm for us on at least some hardware.
> > > 
> > > Yeah, that stinks.  We had another similar report from Patrick:
> > > 
> > >   https://lore.kernel.org/r/CAErSpo5sTeK_my1dEhWp7aHD0xOp87+oHYWkTjbL7ALgDbXo-Q@mail.gmail.com
> > > 
> > > Apparently the problem is ec411e02b7a2 ("PCI/PM: Assume ports without
> > > DLL Link Active train links in 100 ms"), which Patrick found was
> > > backported to v5.4.49 as 828b192c57e8, and you found was backported to
> > > v5.7.6 as afaff825e3a4.
> > > 
> > > Oddly, Patrick reported that v5.7.7 worked correctly, even though it
> > > still contains afaff825e3a4.
> > > 
> > > I guess in the absence of any other clues we'll have to revert it.
> > > I hate to do that because that means we'll have slow resume of
> > > Thunderbolt-connected devices again, but that's better than having
> > > GPUs completely broken.
> > > 
> > > Could you and Patrick open bugzilla.kernel.org reports, attach dmesg
> > > logs and "sudo lspci -vv" output, and add the URLs to Kai-Heng's
> > > original report at https://bugzilla.kernel.org/show_bug.cgi?id=206837
> > > and to this thread?
> > > 
> > > There must be a way to fix the slow resume problem without breaking
> > > the GPUs.
> > > 
> > 
> > I wouldn't be surprised if this is related to the Intel bridge we
> > check against for Nouveau.. I still have to check on another laptop
> > with the same bridge our workaround was required as well but wouldn't
> > be surprised if it shows the same problem. Will get you the
> > information from both systems tomorrow then.
> 
> I take it that ec411e02b7a2 will be reverted upstream?

Yes, unless we have a better fix soon.  I applied the revert to my
for-linus branch, so it will appear in -next soon.  I think it's a
little late to get it in -rc5, so I'll probably ask Linus to pull it
next week for -rc6.

Bjorn

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Lyude Paul]

On Thu, 2020-07-16 at 18:54 -0500, Bjorn Helgaas wrote:
> [+cc Sasha -- stable kernel regression]
> [+cc Patrick, Kai-Heng, LKML]
> 
> On Fri, Jul 17, 2020 at 12:10:39AM +0200, Karol Herbst wrote:
> > On Tue, Jul 7, 2020 at 9:30 PM Karol Herbst <kherbst@redhat.com> wrote:
> > > Hi everybody,
> > > 
> > > with the mentioned commit Nouveau isn't able to load firmware onto the
> > > GPU on one of my systems here. Even though the issue doesn't always
> > > happen I am quite confident this is the commit breaking it.
> > > 
> > > I am still digging into the issue and trying to figure out what
> > > exactly breaks, but it shows up in different ways. Either we are not
> > > able to boot the engines on the GPU or the GPU becomes unresponsive.
> > > Btw, this is also a system where our runtime power management issue
> > > shows up, so maybe there is indeed something funky with the bridge
> > > controller.
> > > 
> > > Just pinging you in case you have an idea on how this could break Nouveau
> > > 
> > > most of the times it shows up like this:
> > > nouveau 0000:01:00.0: acr: AHESASC binary failed
> > > 
> > > Sometimes it works at boot and fails at runtime resuming with random
> > > faults. So I will be investigating a bit more, but yeah... I am super
> > > sure the commit triggered this issue, no idea if it actually causes
> > > it.
> > 
> > so yeah.. I reverted that locally and never ran into issues again.
> > Still valid on latest 5.7. So can we get this reverted or properly
> > fixed? This breaks runtime pm for us on at least some hardware.
> 
> Yeah, that stinks.  We had another similar report from Patrick:
> 
>   
> https://lore.kernel.org/r/CAErSpo5sTeK_my1dEhWp7aHD0xOp87+oHYWkTjbL7ALgDbXo-Q@mail.gmail.com
> 
> Apparently the problem is ec411e02b7a2 ("PCI/PM: Assume ports without
> DLL Link Active train links in 100 ms"), which Patrick found was
> backported to v5.4.49 as 828b192c57e8, and you found was backported to
> v5.7.6 as afaff825e3a4.
> 
> Oddly, Patrick reported that v5.7.7 worked correctly, even though it
> still contains afaff825e3a4.
> 
> I guess in the absence of any other clues we'll have to revert it.
> I hate to do that because that means we'll have slow resume of
> Thunderbolt-connected devices again, but that's better than having
> GPUs completely broken.
> 
> Could you and Patrick open bugzilla.kernel.org reports, attach dmesg
> logs and "sudo lspci -vv" output, and add the URLs to Kai-Heng's
> original report at https://bugzilla.kernel.org/show_bug.cgi?id=206837
> and to this thread?
> 
> There must be a way to fix the slow resume problem without breaking
> the GPUs.

Isn't it possible to tell whether a PCI device is connected through thunderbolt
or not? We could probably get away with just defaulting to 100ms for thunderbolt
devices without DLL Link Active specified, and then default to the old delay
value for non-thunderbolt devices.

> 
> Bjorn
> 

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Lukas Wunner]

On Fri, Jul 17, 2020 at 03:04:10PM -0400, Lyude Paul wrote:
> Isn't it possible to tell whether a PCI device is connected through
> thunderbolt or not? We could probably get away with just defaulting
> to 100ms for thunderbolt devices without DLL Link Active specified,
> and then default to the old delay value for non-thunderbolt devices.

pci_is_thunderbolt_attached()

Re: nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

[Mika Westerberg]

On Fri, Jul 17, 2020 at 09:52:09PM +0200, Lukas Wunner wrote:
> On Fri, Jul 17, 2020 at 03:04:10PM -0400, Lyude Paul wrote:
> > Isn't it possible to tell whether a PCI device is connected through
> > thunderbolt or not? We could probably get away with just defaulting
> > to 100ms for thunderbolt devices without DLL Link Active specified,
> > and then default to the old delay value for non-thunderbolt devices.
> 
> pci_is_thunderbolt_attached()

That only works with some devices. I think we should try to keep the
fact that some PCIe links may be tunneled over TBT/USB4 transparent to
the PCI core and try to treat them as "standard" PCIe links if possible
at all :)