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In-Reply-To: <c3bb7983-86e4-424e-aadd-e82a0cb6ef37@ristioja.ee>
From:   Huacai Chen <chenhuacai@kernel.org>
Date:   Sun, 29 Oct 2023 09:42:52 +0800
Message-ID: <CAAhV-H7UTnTWQeT_qo7VgBczaZo37zjosREr16H8DsLi21XPqQ@mail.gmail.com>
Subject: Re: Blank screen on boot of Linux 6.5 and later on Lenovo ThinkPad L570
To:     Jaak Ristioja <jaak@ristioja.ee>
Cc:     Linux regressions mailing list <regressions@lists.linux.dev>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Javier Martinez Canillas <javierm@redhat.com>,
        Linux DRI Development <dri-devel@lists.freedesktop.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Thorsten Leemhuis <regressions@leemhuis.info>,
        Bagas Sanjaya <bagasdotme@gmail.com>,
        Evan Preston <x.arch@epreston.net>
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On Sat, Oct 28, 2023 at 7:06=E2=80=AFPM Jaak Ristioja <jaak@ristioja.ee> wr=
ote:
>
> On 26.10.23 03:58, Huacai Chen wrote:
> > Hi, Jaak,
> >
> > On Thu, Oct 26, 2023 at 2:49=E2=80=AFAM Jaak Ristioja <jaak@ristioja.ee=
> wrote:
> >>
> >> On 25.10.23 16:23, Huacai Chen wrote:
> >>> On Wed, Oct 25, 2023 at 6:08=E2=80=AFPM Thorsten Leemhuis
> >>> <regressions@leemhuis.info> 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=E2=80=AFPM Linux regression tracking =
(Thorsten
> >>>>>> Leemhuis) <regressions@leemhuis.info> wrote:
> >>>>>>> On 09.10.23 10:54, Huacai Chen wrote:
> >>>>>>>> On Mon, Oct 9, 2023 at 4:45=E2=80=AFPM Bagas Sanjaya <bagasdotme=
@gmail.com> wrote:
> >>>>>>>>> On Mon, Oct 09, 2023 at 09:27:02AM +0800, Huacai Chen wrote:
> >>>>>>>>>> On Tue, Sep 26, 2023 at 10:31=E2=80=AFPM Huacai Chen <chenhuac=
ai@kernel.org> wrote:
> >>>>>>>>>>> On Tue, Sep 26, 2023 at 7:15=E2=80=AFPM Linux regression trac=
king (Thorsten
> >>>>>>>>>>> Leemhuis) <regressions@leemhuis.info> wrote:
> >>>>>>>>>>>> On 13.09.23 14:02, Jaak Ristioja wrote:
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> Upgrading to Linux 6.5 on a Lenovo ThinkPad L570 (Integrate=
d 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 60aebc9559492cea6a9625f514a804=
1717e3a2e4
> >>>>>>>>>>>>> ("drivers/firmware: Move sysfb_init() from device_initcall =
to
> >>>>>>>>>>>>> subsys_initcall_sync").
> >>>>>>>>>>>>
> >>>>>>>>>> As confirmed by Jaak, disabling DRM_SIMPLEDRM makes things wor=
k fine
> >>>>>>>>>> again. So I guess the reason:
> >>>>>>>
> >>>>>>> Well, this to me still looks a lot (please correct me if I'm wron=
g) like
> >>>>>>> regression that should be fixed, as DRM_SIMPLEDRM was enabled bef=
orehand
> >>>>>>> if I understood things correctly. Or is there a proper fix for th=
is
> >>>>>>> already in the works and I just missed this? Or is there some goo=
d
> >>>>>>> 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 h=
as a
> >>>>>> blank screen. Of course it is valuable to investigate further abou=
t
> >>>>>> DRM_SIMPLEDRM on Jaak's machine, but that needs Jaak's effort beca=
use
> >>>>>> I don't have a same machine.
> >>>>
> >>>> Side note: Huacai, have you tried working with Jaak to get down to t=
he
> >>>> real problem? Evan, might you be able to help out here?
> >>> No, Jaak has no response after he 'fixed' his problem by disabling SI=
MPLEDRM.
> >>>
> >>
> >> I'm sorry, what was it exactly you want me to do? Please be mindful th=
at
> >> I'm not familiar with the internals of the Linux kernel and DRI, and i=
t
> >> might sometimes take weeks before I have time to work and respond on t=
his.
> > 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=3Dy and
> get no blank screen with CONFIG_FB_SIMPLE=3Dy and CONFIG_DRM_SIMPLEDRM un=
set.
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 blan=
k
> >>>>> screen after boot and a rapidly flashing device-access-status
> >>>>> indicator.
> >>>>
> >>>> This additional report makes me wonder if we should revert the culpr=
it
> >>>> (60aebc9559492c ("drivers/firmware: Move sysfb_init() from
> >>>> device_initcall to subsys_initcall_sync") [v6.5-rc1]). But I guess t=
hat
> >>>> 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 wi=
th 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/firmwa=
re: Move
> >>>>>>>>>> sysfb_init() from device_initcall to subsys_initcall_sync") th=
ere 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 p=
latform
> >>>>>>>>> device is also none, right?
> >>>>>>>> No. The SIMPLEDRM driver needs a platform device to work, and th=
at
> >>>>>>>> commit makes the platform device created earlier. So, before tha=
t
> >>>>>>>> commit, SIMPLEDRM doesn't work, but the screen isn't blank; afte=
r that
> >>>>>>>> commit, SIMPLEDRM works, but the screen is blank.
> >>>>>>>>
> >>>>>>>> Huacai
> >>>>>>>>>
> >>>>>>>>> Confused...
> >>>>>>>>>
> >>>>>>>>> --
> >>>>>>>>> An old man doll... just what I always wanted! - Clara
> >>>>>>>>
> >>>>>>>>
> >>>>>
> >>>>>
> >>
>