Nouveau - Jul 2020 - nouveau regression with 5.7 caused by "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

On Tue, Jul 7, 2020 at 9:30 PM Karol Herbst <kherbst at 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.
> git bisect log (had to do a second bisect, that's why the first bad
> and good commits appear a bit random):
>
> git bisect start
> # bad: [a92b984a110863b42a3abf32e3f049b02b19e350] clk: samsung:
> exynos5433: Add IGNORE_UNUSED flag to sclk_i2s1
> git bisect bad a92b984a110863b42a3abf32e3f049b02b19e350
> # good: [4da858c086433cd012c0bb16b5921f6fafe3f803] Merge branch
> 'linux-5.7' of git://github.com/skeggsb/linux into drm-fixes
> git bisect good 4da858c086433cd012c0bb16b5921f6fafe3f803
> # good: [d5dfe4f1b44ed532653c2335267ad9599c8a698e] Merge tag
> 'for-linus' of
git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma
> git bisect good d5dfe4f1b44ed532653c2335267ad9599c8a698e
> # good: [b24e451cfb8c33ef5b8b4a80e232706b089914fb] ipv6: fix
> IPV6_ADDRFORM operation logic
> git bisect good b24e451cfb8c33ef5b8b4a80e232706b089914fb
> # good: [d843ffbce812742986293f974d55ba404e91872f] nvmet: fix memory
> leak when removing namespaces and controllers concurrently
> git bisect good d843ffbce812742986293f974d55ba404e91872f
> # good: [be66f10a60e3ec0b589898f78a428bcb34095730] staging: wfx: fix
> output of rx_stats on big endian hosts
> git bisect good be66f10a60e3ec0b589898f78a428bcb34095730
> # good: [a4482984c41f5cc1d217aa189fe51bbbc0500f98] s390/qdio:
> consistently restore the IRQ handler
> git bisect good a4482984c41f5cc1d217aa189fe51bbbc0500f98
> # good: [bec32a54a4de62b46466f4da1beb9ddd42db81b8] f2fs: fix potential
> use-after-free issue
> git bisect good bec32a54a4de62b46466f4da1beb9ddd42db81b8
> # bad: [044aaaa8b1b15adb397ce423a6d97920a46b3893] habanalabs: increase
> timeout during reset
> git bisect bad 044aaaa8b1b15adb397ce423a6d97920a46b3893
> # good: [6fe8ed270763a6a2e350bf37eee0f3857482ed48] arm64: dts: qcom:
> db820c: Fix invalid pm8994 supplies
> git bisect good 6fe8ed270763a6a2e350bf37eee0f3857482ed48
> # good: [363e8bfc96b4e9d9e0a885408cecaf23df468523] tty: n_gsm: Fix
> waking up upper tty layer when room available
> git bisect good 363e8bfc96b4e9d9e0a885408cecaf23df468523
> # bad: [afaff825e3a436f9d1e3986530133b1c91b54cd1] PCI/PM: Assume ports
> without DLL Link Active train links in 100 ms
> git bisect bad afaff825e3a436f9d1e3986530133b1c91b54cd1
> # good: [be0ed15d88c65de0e28ff37a3b242e65a782fd98] HID: Add quirks for
> Trust Panora Graphic Tablet
> git bisect good be0ed15d88c65de0e28ff37a3b242e65a782fd98
> # first bad commit: [afaff825e3a436f9d1e3986530133b1c91b54cd1] PCI/PM:
> Assume ports without DLL Link Active train links in 100 ms

[+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 at 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
at 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

On Fri, Jul 17, 2020 at 1:54 AM Bjorn Helgaas <helgaas at 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 at
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 at
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
>

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 at
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 at
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
>