On Mon, Aug 29, 2016 at 11:02:10AM -0500, Bjorn Helgaas wrote:
> [+cc linux-acpi, linux-kernel, dri-devel]
>
> Hi Roland,
>
> I have no idea how to debug this problem. Are you seeing something
> that suggests it may be a PCI problem?
Yes I suspect there is an ACPI and/ or PCI problem, possibly
device-specific. Steps to reproduce on the affected machines:
1. Load nouveau.
2. Wait for it to runtime suspend.
2. Invoke 'lspci', this resumes the Nvidia PCI device via nouveau.
3. lspci never returns, few moments later an AML_INFINITE_LOOP is
reported.
If you use the external bbswitch module, the effect is the same. I have
been trying to debug this for some time on nouveau with no luck. The
PCI/PM D3cold patches from Mika makes no difference.
Runtime resume via nouveau triggers some ACPI methods (I'll assume the
Windows 8-style PR method and take the Clevo P651 as example):
\_SB.PCI0.PEG0.PG00._ON () ->
\_SB.PCI0.PGON (0)
Then:
Method (PGON, 1, Serialized) {
PION = Arg0 // note: 0 for PG00
// ...
If ((OSYS != 0x07DF)) { /* Not Windows 2015 (Windows 10), see below */ }
Else {
LKEN (PION)
}
// this is the infinite loop: it tries to bring the PCIe link to
// full speed, but fails to do so.
While ((\_SB.PCI0.PEG0.LNKS < 0x07)) {
Local0 = 0x20
While (Local0) {
If ((\_SB.PCI0.PEG0.LNKS < 0x07)) {
Stall (0x64)
Local0--
} Else { Break }
}
If ((Local0 == Zero)) {
\_SB.PCI0.PEG0.RTLK = One
Stall (0x64)
}
}
// ...
}
Without any workaround, this piece of code is invoked:
Method (LKEN, 1, NotSerialized) {
Local3 = (CPEX & 0x0F) // CPEX at 0x5ff9be7f and has value 000506e3
If ((Local3 == Zero)) {
/* Similar to below, but with Q0L0 -> P0L0 (register 0xBC bit 6) */
} ElseIf ((Local3 != Zero)) {
If ((Arg0 == Zero)) {
/* Enter L0 Activate state.
* (LKDS tries to enter L2, deep-energy-saving state.) */
Q0L0 = One // register 0x249 bit 0; \_SB.PCI0.OPG0.Q0L0 00:01.0
Sleep (0x10)
Local0 = Zero
While (Q0L0) {
If ((Local0 > 0x04)) { Break }
Sleep (0x10)
Local0++
}
} else { /* other cases, but we are only interested in PGON(0) */ }
}
}
The acpi_osi="!Windows 2015" workaround will invoke this instead:
If ((OSYS != 0x07DF)) {
If ((PION == Zero)) {
P0AP = Zero /* PGOF writes 3 */
P0RM = Zero /* PGOF writes 1 */
}
If ((PBGE != Zero)) { /* Observed to be false (PBGE == 0) */
If (SBDL (PION)) {
PUAB (PION)
CBDL = GUBC (PION)
MBDL = GMXB (PION)
If ((CBDL > MBDL)) {
CBDL = MBDL /* \_SB_.PCI0.MBDL */
}
PDUB (PION, CBDL)
}
}
If ((PION == Zero)) {
P0LD = Zero /* Link Disable = 0, PGOF sets 1 instead. */
P0TR = One /* Train? (PGOF does not set this). */
TCNT = Zero
While ((TCNT < LDLY)) { /* LDLY = 300 */
If ((P0VC == Zero)) {
/* VC Negotiation Pending 0 means VC negotation is complete. */
Break
}
Sleep (0x10)
TCNT += 0x10 /* At most 19 iterations, sleeping for 304ms. */
}
}
}
The comments above are my own interpretation based on the acpidumps I
extracted from the machine. These notes and ACPI tables can be found at
https://github.com/Lekensteyn/acpi-stuff/blob/master/Clevo-P651RA/notes.txt
https://github.com/Lekensteyn/acpi-stuff/tree/master/dsl/Clevo_P651RA
Other affected devices have similar code, differences are small:
- No check for LNKS (avoids the infinite loop, but device is still off)
- Instead of a check for != "Windows 2015", they check for == "Windows
2009" or even for == "Windows 2009" || "Windows 2013" (Dell Inspiron
7559).
The tested kernels (with bbswitch or nouveau) were Linux 4.4.0, 4.6,
4.7 (nouveau + PCI/PM + nouveau PR patches). The PCIe device is
something from the GTX 9xxM family in all cases.
I have a bunch of PCI config dumps from Windows and Linux, but there is
nothing extraordinary. Also did an ACPI trace via a Checked/Debug build
of Windows, but it just confirms that the ACPI method we use for the
Nvidia device is the correct one.
Let me know if you need more information, I would be glad to provide.
Kind regards,
Peter
> On Tue, Aug 23, 2016 at 11:23:45AM +0200, Roland Singer wrote:
> > Hi,
> >
> > hope somebody can help me fix this kernel problem which affects the following machines:
> >
> > - Clevo P651RA (i7-6700HQ/GTX 965M, part of the P6xxRx family which are also affected)
> > - MSI GE62 Apache Pro (i7-6700HQ/GTX 960M)
> > - Gigabyte P35V5 (i7-6700HQ/GTX 970M)
> > - Razer Blade 14" (2016) (i7-6700HQ/GTX 970M) (BIOS 5.11, 04/07/2016)
> >
> >
> > The kernel freezes if the graphical user session (Xorg & Wayland) is
> > started with a switched off discrete GPU card (NVIDIA).
> > If the discrete GPU is switched off after the graphical session start,
> > then everything works as expected, until the graphical session is restarted.
> >
> > This problem seams to be linked to specific BIOS settings. If the computer
> > is started with the following command line:
> >
> > acpi_osi=! acpi_osi="Windows 2009"
> >
> > then the kernel freeze does not occur anymore. However this required a special
> > ACPI DSDT firmware patch for the Razer Blade 2016 laptop:
> >
> > https://github.com/m4ng0squ4sh/razer_blade_14_2016_acpi_dsdt
> >
> > I strongly recommend to fix this in the kernel and I am ready to help and solve
> > this problem with some help.
> >
> > Here is a link to the GitHub issue with further information:
> >
> > https://github.com/Bumblebee-Project/Bumblebee/issues/764#issuecomment-241212595
> >
> > Here are some more detailed information:
> >
> > https://github.com/Lekensteyn/acpi-stuff/blob/master/Clevo-P651RA/notes.txt
> >
> > Hope somebody can help.
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