On 6/30/2023 14:39, Bjorn Helgaas wrote:
On Fri, Jun 30, 2023 at 02:30:56PM -0500, Limonciello, Mario wrote:
Hi Bjorn,
For the _REG change that went into Linus' tree I was recently made aware of
another system that it helps.
This system was appearing to hang during bootup which evaluating the USB4
_OSC.
This hang happened on both the 6.1 LTS kernel and 6.4 final kernel.
In looking at the BIOS debug log shared by the reporter I noticed that
the kernel isn't hung it's just that the BIOS was waiting to be given the
ability to access the config space.
Backporting just that _REG patch onto 6.1 LTS kernel fixes the issue.
I'm encouraging the BIOS team to try to come up with a cleaner failure path
for the lack of _REG being called. However there is always the possibility
they can't or choose not to and people try to boot older kernels and fail.
Given how severe this boot issue is compared to the original suspend issue
that prompted the patch I wanted to gauge how you feel about the risk of
taking this change back to stable.
I think we can do that. But the patch is already in the pull request
for v6.5, so we'll have to wait until Linus pulls it and then ask the
stable folks to pick it up. I don't think it should be a big deal; we
just need a mainline SHA1 for it.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/stable-kernel-rules.rst?id=v6.4#n64
OK thanks, I saw your PR was sent out but I didn't realize it wasn't
picked yet.
I'll keep an eye out for when the SHA1 is in Linus' tree and I'll
request it for stable when it is.
