Re: [PATCH 0/6] accel/ivpu: Changes for 6.15 2025-02-04

[Thomas Zimmermann <tzimmermann@suse.de>]

Hi,

here's a complaint about the lack of process and documentation in 
accel/, and ivpu specifically. I came across this series while preparing 
the weekly PR for drm-misc-next and found myself unable to extract much 
useful information to report. This is a problem for a development 
process that relies on transparency, accountability and collaboration. 
Other problematic examples are at [1] and [2]. IIRC I had similar issues 
in previous development cycles.

I cannot assess the quality of the code itself, but the process and 
documentation involved does not meet the requirements.

- 'Changes for <version>' is not an meaningful description for a patch 
series. It's not the submitter (or anyone else) deciding that this 
series gets merged into version so-and-so. The series gets merged when 
it is ready to be merged.

- Apparently this series contains 3 different things (buffer imports, 
locking, debugging); so it should be 3 series with each addressing one 
of these topics.

- The series' description just restates the patch descriptions briefly. 
It should rather give some indication of the problem being solved by the 
contained patches, and context on why this is worth solving. (I know 
that this is often complicated to state clearly to outsiders.)

- Review should be public. I understand that it's often only one dev 
team working on a specific driver, discussing issues internally. Still 
it makes sense to do the code reviews in public, so that others can 
follow what is going on in the driver. Public code reviews are also 
necessary to establish consent and institutional knowledge within the 
wider developer community. You miss that with internal reviews.

- These patches come with R-b tags pre-applied. Even for trivial 
changes, R-b tags should given in public. If the R-bs have been given 
elsewhere, please include a reference to that location. The tags (R-b, 
A-b, T-b, etc) are not just for verifying the code itself. They also 
establish trust in the development process involving each patch; and in 
the developers involved in that process. This needs to happen in public 
to be effective.

- The kernel's (or any FOSS') development is organized around 
individuals, not organizations. Having each developer send their changes 
individually would likely resolve most of the current problems.

I understand that accel is not graphics and can feel somewhat detached 
from the rest of DRM. Yet it is part of the DRM subsystem. This 
development cycles' ivpu series' made me go to IRC and ask for accel/ to 
be removed from the drm-misc tree. Luckily the other maintainer were 
more charitable. So I make these remarks in good faith and hope that we 
can improve the processes within accel/.

Best regards
Thomas

[1] https://patchwork.freedesktop.org/series/143182/
[2] https://patchwork.freedesktop.org/series/144101/


Am 04.02.25 um 09:46 schrieb Jacek Lawrynowicz:
> Add possibility to import single buffer into multiple contexts,
> fix locking when aborting contexts and add some debug features.
>
> Andrzej Kacprowski (2):
>    accel/ivpu: Add missing locks around mmu queues
>    accel/ivpu: Prevent runtime suspend during context abort work
>
> Karol Wachowski (3):
>    ccel/ivpu: Add debugfs interface for setting HWS priority bands
>    accel/ivpu: Add test modes to toggle clock relinquish disable
>    accel/ivpu: Implement D0i2 disable test modea
>
> Tomasz Rusinowicz (1):
>    accel/ivpu: Allow to import single buffer into multiple contexts
>
>   drivers/accel/ivpu/ivpu_debugfs.c | 84 +++++++++++++++++++++++++++++++
>   drivers/accel/ivpu/ivpu_drv.c     |  2 +-
>   drivers/accel/ivpu/ivpu_drv.h     |  4 ++
>   drivers/accel/ivpu/ivpu_fw.c      |  4 ++
>   drivers/accel/ivpu/ivpu_gem.c     | 43 ++++++++++++++++
>   drivers/accel/ivpu/ivpu_gem.h     |  1 +
>   drivers/accel/ivpu/ivpu_hw.c      | 31 ++++++++++++
>   drivers/accel/ivpu/ivpu_hw.h      |  5 ++
>   drivers/accel/ivpu/ivpu_job.c     | 10 +++-
>   drivers/accel/ivpu/ivpu_jsm_msg.c | 29 ++++-------
>   drivers/accel/ivpu/ivpu_mmu.c     |  9 ++++
>   11 files changed, 202 insertions(+), 20 deletions(-)
>
> --
> 2.45.1

-- 
--
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)