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

[Huacai Chen]

Hi, Jaak,

On Thu, Oct 26, 2023 at 2:49 AM Jaak Ristioja <jaak@xxxxxxxxxxx> wrote:
>
> On 25.10.23 16:23, Huacai Chen wrote:
> > 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.
> >
>
> I'm sorry, what was it exactly you want me to do? Please be mindful that
> I'm not familiar with the internals of the Linux kernel and DRI, and it
> might sometimes take weeks before I have time to work and respond on this.
It doesn't matter. I hope you can do some experiments to investigate
deeper. The first experiment you can do is enabling SIMPLEFB (i.e.
CONFIG_FB_SIMPLE) instead of SIMPLEDRM (CONFIG_DRM_SIMPLEDRM) to see
whether there is also a blank screen. If no blank screen, that
probably means SIMPLEDRM has a bug, if still blank screen, that means
the firmware may pass wrong screen information.

Huacai

>
> Jaak
>
> >>
> >> 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
> >>>>>>
> >>>>>>
> >>>
> >>>
>