Date:   Sat, 28 Oct 2023 14:06:18 +0300
From:   Jaak Ristioja <jaak@...tioja.ee>
To:     Huacai Chen <chenhuacai@...nel.org>
Cc:     Thorsten Leemhuis <regressions@...mhuis.info>,
        Evan Preston <x.arch@...eston.net>,
        Linux regressions mailing list <regressions@...ts.linux.dev>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Javier Martinez Canillas <javierm@...hat.com>,
        Linux DRI Development <dri-devel@...ts.freedesktop.org>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Bagas Sanjaya <bagasdotme@...il.com>
Subject: Re: Blank screen on boot of Linux 6.5 and later on Lenovo ThinkPad
 L570

On 26.10.23 03:58, Huacai Chen wrote:
> Hi, Jaak,
> 
> On Thu, Oct 26, 2023 at 2:49 AM Jaak Ristioja <jaak@...tioja.ee> wrote:
>>
>> On 25.10.23 16:23, Huacai Chen wrote:
>>> On Wed, Oct 25, 2023 at 6:08 PM Thorsten Leemhuis
>>> <regressions@...mhuis.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 PM Linux regression tracking (Thorsten
>>>>>> Leemhuis) <regressions@...mhuis.info> wrote:
>>>>>>> On 09.10.23 10:54, Huacai Chen wrote:
>>>>>>>> On Mon, Oct 9, 2023 at 4:45 PM Bagas Sanjaya <bagasdotme@...il.com> 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@...nel.org> wrote:
>>>>>>>>>>> On Tue, Sep 26, 2023 at 7:15 PM Linux regression tracking (Thorsten
>>>>>>>>>>> Leemhuis) <regressions@...mhuis.info> 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.

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
>>>>>>>>
>>>>>>>>
>>>>>
>>>>>
>>

Powered by blists - more mailing lists