Re: Blank screen on boot of Linux 6.5 and later on Lenovo ThinkPad L570

[Huacai Chen]

On Wed, Oct 25, 2023 at 6:08 PM Thorsten Leemhuis
<regressions@xxxxxxxxxxxxx> wrote:
>
> Javier, Dave, Sima,
>
> On 23.10.23 00:54, Evan Preston wrote:
> > On 2023-10-20 Fri 05:48pm, Huacai Chen wrote:
> >> On Fri, Oct 20, 2023 at 5:35 PM Linux regression tracking (Thorsten
> >> Leemhuis) <regressions@xxxxxxxxxxxxx> wrote:
> >>> On 09.10.23 10:54, Huacai Chen wrote:
> >>>> On Mon, Oct 9, 2023 at 4:45 PM Bagas Sanjaya <bagasdotme@xxxxxxxxx> wrote:
> >>>>> On Mon, Oct 09, 2023 at 09:27:02AM +0800, Huacai Chen wrote:
> >>>>>> On Tue, Sep 26, 2023 at 10:31 PM Huacai Chen <chenhuacai@xxxxxxxxxx> wrote:
> >>>>>>> On Tue, Sep 26, 2023 at 7:15 PM Linux regression tracking (Thorsten
> >>>>>>> Leemhuis) <regressions@xxxxxxxxxxxxx> wrote:
> >>>>>>>> On 13.09.23 14:02, Jaak Ristioja wrote:
> >>>>>>>>>
> >>>>>>>>> Upgrading to Linux 6.5 on a Lenovo ThinkPad L570 (Integrated Intel HD
> >>>>>>>>> Graphics 620 (rev 02), Intel(R) Core(TM) i7-7500U) results in a blank
> >>>>>>>>> screen after boot until the display manager starts... if it does start
> >>>>>>>>> at all. Using the nomodeset kernel parameter seems to be a workaround.
> >>>>>>>>>
> >>>>>>>>> I've bisected this to commit 60aebc9559492cea6a9625f514a8041717e3a2e4
> >>>>>>>>> ("drivers/firmware: Move sysfb_init() from device_initcall to
> >>>>>>>>> subsys_initcall_sync").
> >>>>>>>>
> >>>>>> As confirmed by Jaak, disabling DRM_SIMPLEDRM makes things work fine
> >>>>>> again. So I guess the reason:
> >>>
> >>> Well, this to me still looks a lot (please correct me if I'm wrong) like
> >>> regression that should be fixed, as DRM_SIMPLEDRM was enabled beforehand
> >>> if I understood things correctly. Or is there a proper fix for this
> >>> already in the works and I just missed this? Or is there some good
> >>> reason why this won't/can't be fixed?
> >>
> >> DRM_SIMPLEDRM was enabled but it didn't work at all because there was
> >> no corresponding platform device. Now DRM_SIMPLEDRM works but it has a
> >> blank screen. Of course it is valuable to investigate further about
> >> DRM_SIMPLEDRM on Jaak's machine, but that needs Jaak's effort because
> >> I don't have a same machine.
>
> Side note: Huacai, have you tried working with Jaak to get down to the
> real problem? Evan, might you be able to help out here?
No, Jaak has no response after he 'fixed' his problem by disabling SIMPLEDRM.

>
> But I write this mail for a different reason:
>
> > I am having the same issue on a Lenovo Thinkpad P70 (Intel
> > Corporation HD Graphics 530 (rev 06), Intel(R) Core(TM) i7-6700HQ).
> > Upgrading from Linux 6.4.12 to 6.5 and later results in only a blank
> > screen after boot and a rapidly flashing device-access-status
> > indicator.
>
> This additional report makes me wonder if we should revert the culprit
> (60aebc9559492c ("drivers/firmware: Move sysfb_init() from
> device_initcall to subsys_initcall_sync") [v6.5-rc1]). But I guess that
> might lead to regressions for some users? But the patch description says
> that this is not a common configuration, so can we maybe get away with that?
>From my point of view, this is not a regression, 60aebc9559492c
doesn't cause a problem, but exposes a problem. So we need to fix the
real problem (SIMPLEDRM has a blank screen on some conditions). This
needs Jaak or Evan's help.

Huacai
>
> Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
> --
> Everything you wanna know about Linux kernel regression tracking:
> https://linux-regtracking.leemhuis.info/about/#tldr
> If I did something stupid, please tell me, as explained on that page.
>
> >>>>>> When SIMPLEDRM takes over the framebuffer, the screen is blank (don't
> >>>>>> know why). And before 60aebc9559492cea6a9625f ("drivers/firmware: Move
> >>>>>> sysfb_init() from device_initcall to subsys_initcall_sync") there is
> >>>>>> no platform device created for SIMPLEDRM at early stage, so it seems
> >>>>>> also "no problem".
> >>>>> I don't understand above. You mean that after that commit the platform
> >>>>> device is also none, right?
> >>>> No. The SIMPLEDRM driver needs a platform device to work, and that
> >>>> commit makes the platform device created earlier. So, before that
> >>>> commit, SIMPLEDRM doesn't work, but the screen isn't blank; after that
> >>>> commit, SIMPLEDRM works, but the screen is blank.
> >>>>
> >>>> Huacai
> >>>>>
> >>>>> Confused...
> >>>>>
> >>>>> --
> >>>>> An old man doll... just what I always wanted! - Clara
> >>>>
> >>>>
> >
> >