Re: Fwd: [Bug 199879] New: Very basic the Pci device is not resumed from suspend mode

[Bjorn Helgaas <helgaas@kernel.org>]

[+to Rafal]

Sorry, I'm an idiot and forgot to include Rafal, the submitter, when I
forwarded this report to the mailing lists.

I suspect that the config accessors used by lspci should temporarily
wake up devices that are asleep, instead of reporting 0xff data (or if
that's not feasible, maybe we should add a comment in the kernel and a
note in the lspci man page).

I'm not sure yet where to go beyond that.

On Wed, May 30, 2018 at 07:41:35AM -0700, Bjorn Helgaas wrote:
> [+cc linux-pci, linux-kernel, linux-pm]
> 
> I'm not sure I understand the problem yet, so please correct me if I'm wrong:
> 
>   - Your system has both Nvidia and Intel graphics devices
> 
>   - When you use Intel graphics, lspci, lshw, and /proc/bus/pci for
> the Nvidia device show invalid data (0xff) after suspend/resume
> 
>   - When you use Nvidia graphics, suspend/resume doesn't work (instead
> of resuming, you just get a blank screen)
> 
> Can you attach the output of "sudo lspci -vv" to the bugzilla, please?
> 
> ---------- Forwarded message ---------
> From: <bugzilla-daemon@bugzilla.kernel.org>
> Date: Tue, May 29, 2018 at 1:29 PM
> Subject: [Bug 199879] New: Very basic the Pci device is not resumed
> from suspend mode
> To: <bhelgaas@google.com>
> 
> 
> https://bugzilla.kernel.org/show_bug.cgi?id=199879
> 
>             Bug ID: 199879
>            Summary: Very basic the Pci device is not resumed from suspend
>                     mode
>            Product: Drivers
>            Version: 2.5
>     Kernel Version: kernel-4.15.17
>           Hardware: x86-64
>                 OS: Linux
>               Tree: Mainline
>             Status: NEW
>           Severity: high
>           Priority: P1
>          Component: PCI
>           Assignee: drivers_pci@kernel-bugs.osdl.org
>           Reporter: uzg@wp.pl
>         Regression: No
> 
> Hi, I have problem with very basic device. Device pci-e not resume from
> suspend. Only sleep.
> 
> I have a problem with anyone interested in it, because everyone thinks it is
> the fault of the device drivers themselves. But this is not a problem.
> 
> This device is a basic device. I've already installed drivers on various
> hardware and it has always been ok, but not this time.
> 
> I'm an electronics technician. After diagnosing what I managed, in my opinion
> the device remains asleep.
> 
> Where does my application come from?
> I have multiuser mode and I do not use this device. After suspend lspci and
> lshw show normal data. Normal data is in /proc/bus/pci/...
> Next suspend and resume, and...
> lspci see hardware, but is error
> lshw see hardware as undefined device
> data in /proc/bus/pci/... is only 0xFF
> Hardware sleep, not work, not ready. This is bug.
> 
> But since the problem concerns the graphics card in the configuration with the
> second default Intel card, everyone thinks that this is another driver problem
> as always and nobody wants to take a look at it :(
> 
> The problem is easy to recognize. On the internet, I've seen a lot of
> unresolved problems in which I could see exactly what I found.
> 
> My hardware is Lenovo with NVidia and Intel Graphics. Problem is with NVidia. I
> tested Z710 and Z50-70. The first symptom of the problem is lspci in multiuser
> mode (or when is XServer with intel graphics). After suspend NVidia have e.g
> "rev. A1", after resume is "rev. FF". Next symptom lshw and /proc/bus/pci/...
> When system started with normal NVidia driver, system not resume and halt, only
> black screen.
> 
> There are many examples on the Internet with unsolved problems e.g
> https://www.lwks.com/index.php?option=com_kunena&func=view&catid=21&id=124374&Itemid=81
> 
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