linux-kernel - Re: [PATCH RFC drm-next 0/1] Add support for drm

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Message-ID: <308c1a27-1239-4145-8191-7510986ff256@suse.de>
Date: Thu, 3 Apr 2025 09:23:23 +0200
From: Thomas Zimmermann <tzimmermann@...e.de>
To: Ryosuke Yasuoka <ryasuoka@...hat.com>
Cc: maarten.lankhorst@...ux.intel.com, mripard@...nel.org, airlied@...il.com,
 simona@...ll.ch, drawat.floss@...il.com, jfalempe@...hat.com,
 dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
 linux-hyperv@...r.kernel.org
Subject: Re: [PATCH RFC drm-next 0/1] Add support for drm_panic

Hi

Am 02.04.25 um 15:52 schrieb Ryosuke Yasuoka:
> On Wed, Apr 2, 2025 at 6:45 PM Thomas Zimmermann <tzimmermann@...e.de> wrote:
>> Hi
>>
>> Am 02.04.25 um 10:43 schrieb Ryosuke Yasuoka:
>>> This patch adds drm_panic support for hyperv-drm driver. This function
>>> works but it's still needed to brush up. Let me hear your opinions.
>>>
>>> Once kernel panic occurs we expect to see a panic screen. However, to
>>> see the screen, I need to close/re-open the graphic console client
>>> window. As the panic screen shows correctly in the small preview
>>> window in Hyper-V manager and debugfs API for drm_panic works correctly,
>>> I think kernel needs to send signal to Hyper-V host that the console
>>> client refreshes, but I have no idea what kind of signal is needed.
>>>
>>> This patch is tested on Hyper-V 2022.
>>>
>>> Ryosuke Yasuoka (1):
>>>     drm/hyperv: Add support for drm_panic
>>>
>>>    drivers/gpu/drm/drm_simple_kms_helper.c     | 26 +++++++++++++
>>>    drivers/gpu/drm/hyperv/hyperv_drm_modeset.c | 42 +++++++++++++++++++++
>>>    include/drm/drm_simple_kms_helper.h         | 22 +++++++++++
>> No changes to simple_kms_helper please. This is obsolete and should go
>> away. Just put everything into hyperv_drm.
> OK. Maybe it will work without any modification in simple_kms_helper if we can
> call the pipe->funcs from draw_panic_plane() like drm_plane_helper_funcs.

No problem about that. Feel free to open-code everything that you need 
in the hyperv driver.

>
> Currently, the hyperv_drm is implemented with a simple display pipeline.
> The pipeline control functions are in pipe->funcs and they will call via
> drm_simple_kms_palne_helper_funcs. And these helper functions will
> be called by drm_panic_plane().

Someone should update the hyperv driver to not use simple pipe.

Best regards
Thomas

>
> Thank you for your comment.
> Ryosuke
>
>> Best regards
>> Thomas
>>
>>>    3 files changed, 90 insertions(+)
>>>
>>>
>>> base-commit: cf05922d63e2ae6a9b1b52ff5236a44c3b29f78c
>> --
>> --
>> Thomas Zimmermann
>> Graphics Driver Developer
>> SUSE Software Solutions Germany GmbH
>> Frankenstrasse 146, 90461 Nuernberg, Germany
>> GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
>> HRB 36809 (AG Nuernberg)
>>

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)