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

[Huacai Chen]

On Sat, Oct 28, 2023 at 7:06 PM Jaak Ristioja <jaak@xxxxxxxxxxx> wrote:
>
> On 26.10.23 03:58, Huacai Chen wrote:
> > 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.
>
> Testing with 6.5.9 I get a blank screen with CONFIG_DRM_SIMPLEDRM=y and
> get no blank screen with CONFIG_FB_SIMPLE=y and CONFIG_DRM_SIMPLEDRM unset.
CONFIG_FB_SIMPLE and  CONFIG_DRM_SIMPLEDRM use the same device created
by sysfb_init(). Since FB_SIMPLE works fine, I think the real problem
is that DRM_SIMPLEDRM has a bug. The next step is to enable
CONFIG_DRM_SIMPLEDRM and trace its initialization. In detail, adding
some printk() in simpledrm_probe() and its sub-routines to see where
the driver fails. The output of these printk() can be seen by the
'dmesg' command after boot.

Huacai

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