Re: [REGRESSION] PCI v5.5-rc1 breaks google kevin

From: Vicente Bergas
Date: Thu Dec 12 2019 - 13:40:14 EST

On Thursday, December 12, 2019 3:16:25 PM CET, Enric Balletbo Serra wrote:
Hi Vicente,

Missatge de Andrew Murray <andrew.murray@xxxxxxx> del dia dj., 12 de
des. 2019 a les 1:53:

On Thu, Dec 12, 2019 at 12:12:56AM +0000, Robin Murphy wrote:
Hi Vicente,

On 2019-12-11 11:38 pm, Vicente Bergas wrote:
since v5.5-rc1 the google kevin chromebook does not boot.
Git bisect reports 5e0c21c75e8c PCI/ASPM: Remove pcie_aspm_enabled()
unnecessary locking
as the first bad commit.

In order to revert it from v5.5-rc1 i had to also revert some dependencies:
After reverting all of this, still no luck.
So, either the results of git bisect are not to be trusted, or
there are more bad commits.

By "does not boot" i mean that the display fails to start and
the display is the only output device, so debugging is quite difficult.

Another issue that is affecting current mainline for kevin is fixed
with [1]. As usual, I have a tracking branch for 5.5 for different
Chromebooks with some not yet merged patches that makes things work
while are not fixed [2]. For kevin only the mentioned ASoC patch [1]
and the pcie fix [3] should be needed. Other than that display is
working for me on Kevin.



Assuming it's a manifestation of the same PCI breakage that Enric and
Lorenzo figured out, there's a proposed fix here:

It's likely that any PCI driver that uses PCI IO with that controller will
suffer the same fate.

Vicente - can you try the patch that has been proposed and verify it fixes
the issue for you?


Andrew Murray


v5.5-rc1 as is (reverting no commits at all) works fine when disabling PCI:
# CONFIG_PCI is not set


Hi Robin, Andrew and Enric,
thank you all for the quick responses!
I can confirm that patch [3] fixes the issue reported in this email and
that [1] fixes the other issue reported on the other email.