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From: "Krzysztof Wilczyński" <kw@linux.com>
To: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: Bjorn Helgaas <helgaas@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Oliver O'Halloran <oohall@gmail.com>,
	linux-pci@vger.kernel.org
Subject: Re: [REGRESSION] 527139d738d7 ("PCI/sysfs: Convert "rom" to static attribute")
Date: Fri, 17 Dec 2021 23:49:19 +0100	[thread overview]
Message-ID: <Yb0T79vFgeRcA2OU@rocinante> (raw)
In-Reply-To: <YbzMyDm+5PCer8Fj@intel.com>

Hi Ville,

Thank you for letting us know, and sincere apologies for troubles!

[...]
> > > The pci sysfs "rom" file has disappeared for VGA devices.
> > > Looks to be a regression from commit 527139d738d7 ("PCI/sysfs:
> > > Convert "rom" to static attribute").
> > > 
> > > Some kind of ordering issue between the sysfs file creation 
> > > vs. pci_fixup_video() perhaps?
> > 
> > Can you attach your complete "lspci -vv" output?  Also, which is the
> > default device?  I think there's a "boot_vga" sysfs file that shows
> > this.  "find /sys -name boot_vga | xargs grep ."
> 
> All I have is Intel iGPUs so it's always 00:02.0. 
> 
> $ cat /sys/bus/pci/devices/0000\:00\:02.0/boot_vga 
> 1
> $ cat /sys/bus/pci/devices/0000\:00\:02.0/rom
> cat: '/sys/bus/pci/devices/0000:00:02.0/rom': No such file or directory
> 
> I've attached the full lspci from my IVB laptop, but the problem
> happens on every machine (with an iGPU at least).
> 
> I presume with a discrete GPU it might not happen since they
> actually have a real ROM.

Admittedly, the automated testing I was running before the patch was released
didn't catch this.  I primarily focused on trying to catch the race condition
related to the ROM attribute creation.

I need to look into how to properly address this problem as if we were to
revert the ROM attribute changes, then we would introduce the race condition
we've had back.

Again, apologies for troubles this caused!

	Krzysztof

  reply	other threads:[~2021-12-17 22:49 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-17 10:44 Ville Syrjälä
2021-12-17 17:29 ` Bjorn Helgaas
2021-12-17 17:45   ` Ville Syrjälä
2021-12-17 22:49     ` Krzysztof Wilczyński [this message]
2022-01-20 13:19       ` Thorsten Leemhuis
2022-01-20 15:00         ` Bjorn Helgaas
2022-01-20 15:05           ` Thorsten Leemhuis
2022-01-22  0:24     ` Bjorn Helgaas
2022-01-25 18:56       ` Ville Syrjälä
2021-12-18  6:10 ` Thorsten Leemhuis

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