Hi Greg,
On Fri, Oct 17, 2025 at 08:58:20AM +0200, Greg Kroah-Hartman wrote:
On Thu, Oct 16, 2025 at 08:15:46AM -0700, Brian Norris wrote:
Hi,
On Thu, Oct 16, 2025 at 03:09:27PM +0200, Greg Kroah-Hartman wrote:
This is a note to let you know that I've just added the patch titled
PCI/sysfs: Ensure devices are powered for config readsto the 6.6-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: pci-sysfs-ensure-devices-are-powered-for-config-reads.patch and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
Adding to the stable tree is good IMO, but one note about exactly how to do so below:
Wrap these access in pci_config_pm_runtime_{get,put}() like most of the rest of the similar sysfs attributes.
Notably, "max_link_speed" does not access config registers; it returns a cached value since d2bd39c0456b ("PCI: Store all PCIe Supported Link Speeds").
^^ This note about commit d2bd39c0456b was specifically to provide hints about backporting. Without commit d2bd39c0456b, the solution is somewhat incomplete. We should either backport commit d2bd39c0456b as well, or we should adapt the change to add pci_config_pm_runtime_{get,put}() in max_link_speed_show() too.
I missed that "hint", you need to make it bindingly obvious as I churn through the giant "-rc1 merge dump" very quickly as obviously those are changes that were not serious enough to make it into -final :)
Oh, no, I didn't mean to imply you "missed" anything. It was more of a self-help comment, so I could refer to it when following up here. Otherwise, I also might not trivially remember which commit was involved. And I didn't know at the time how many branches would contain commit d2bd39c0456b.
Sorry if my wording was a bit off.
Commit d2bd39c0456b was already ported to 6.12.y, but seemingly no further.
If adapting this change to pre-commit-d2bd39c0456b is better, I can submit an updated version here.
Without commit d2bd39c0456b, it just means that the 'max_link_speed' sysfs attribute is still susceptible to accessing a powered-down device/link. We're in no worse state than we were without this patch. And frankly, people are not likely to notice if they haven't already, since I'd guess most systems don't suspend devices this aggressively.
I'll gladly accept a fixed up patch for this, thanks.
I'll try to get that out today.
Brian