Message-ID: <31ed0db1-9398-4c46-a391-fc644ec49268@ristioja.ee>
Date:   Wed, 1 Nov 2023 13:52:47 +0200
From:   Jaak Ristioja <jaak@...tioja.ee>
To:     Huacai Chen <chenhuacai@...nel.org>
Cc:     Linux regressions mailing list <regressions@...ts.linux.dev>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Javier Martinez Canillas <javierm@...hat.com>,
        Linux DRI Development <dri-devel@...ts.freedesktop.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Thorsten Leemhuis <regressions@...mhuis.info>,
        Bagas Sanjaya <bagasdotme@...il.com>,
        Evan Preston <x.arch@...eston.net>
Subject: Re: Blank screen on boot of Linux 6.5 and later on Lenovo ThinkPad
 L570

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@...nel.org> wrote:
>>
>> On Sat, Oct 28, 2023 at 7:06 PM Jaak Ristioja <jaak@...tioja.ee> wrote:
>>>
>>> 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.
>> 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
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>
>>>

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