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

[Jaak Ristioja]

On 31.10.23 14:17, Huacai Chen wrote:
> Hi, Jaak and Evan,
>
> On Sun, Oct 29, 2023 at 9:42 AM Huacai Chen <chenhuacai@xxxxxxxxxx> wrote:
> > 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.
> I need your help. I tried with my laptop (ThinkPad E490, Intel Core
> i3-8145U, UHD Graphics 620) but I can't reproduce your problem. So
> please patch your 6.5.x kernel with this temporary patch [1], then
> build a "bad kernel" with SIMPLEDRM enabled. And after booting your
> machine with this "bad kernel", please give me the dmesg output. Thank
> you very much.
>
> [1] http://ddns.miaomiaomiao.top:9000/download/kernel/patch-6.5.9

I'm unable to download it. Can you please send it by e-mail?

Jaak

> Huacai
>
> > 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