On Sun, Oct 22, 2023 at 4:50 PM Dmitry Osipenko <
dmitry.osipenko@collabora.com> wrote:

> On 10/18/23 21:17, Gurchetan Singh wrote:
> > There are two problems with the current method of determining the
> > virtio-gpu debug name.
> >
> > 1) TASK_COMM_LEN is defined to be 16 bytes only, and this is a
> >    Linux kernel idiom (see PR_SET_NAME + PR_GET_NAME). Though,
> >    Android/FreeBSD get around this via setprogname(..)/getprogname(..)
> >    in libc.
> >
> >    On Android, names longer than 16 bytes are common.  For example,
> >    one often encounters a program like "com.android.systemui".
> >
> >    The virtio-gpu spec allows the debug name to be up to 64 bytes, so
> >    ideally userspace should be able to set debug names up to 64 bytes.
> >
> > 2) The current implementation determines the debug name using whatever
> >    task initiated virtgpu.  This is could be a "RenderThread" of a
> >    larger program, when we actually want to propagate the debug name
> >    of the program.
> >
> > To fix these issues, add a new CONTEXT_INIT param that allows userspace
> > to set the debug name when creating a context.
> >
> > It takes a null-terminated C-string as the param value. The length of the
> > string (excluding the terminator) **should** be <= 64 bytes.  Otherwise,
> > the debug_name will be truncated to 64 bytes.
> >
> > Link to open-source userspace:
> >
> https://android-review.googlesource.com/c/platform/hardware/google/gfxstream/+/2787176
> >
> > Signed-off-by: Gurchetan Singh <gurchetansingh@chromium.org>
> > Reviewed-by: Josh Simonot <josh.simonot@gmail.com>
> > ---
> > Fixes suggested by Dmitry Osipenko
> > v2:
> >     - Squash implementation and UAPI change into one commit
> >     - Avoid unnecessary casts
> >     - Use bool when necessary
> > v3:
> >     - Use DEBUG_NAME_MAX_LEN - 1 when copying string
> >
> >  drivers/gpu/drm/virtio/virtgpu_drv.h   |  5 ++++
> >  drivers/gpu/drm/virtio/virtgpu_ioctl.c | 39 ++++++++++++++++++++++----
> >  include/uapi/drm/virtgpu_drm.h         |  2 ++
> >  3 files changed, 40 insertions(+), 6 deletions(-)
>
> Gerd, do you have objections to this UAPI change?
>

Bump.  I say we wait another week and see if anyone cares [I suspect nobody
does].


https://drm.pages.freedesktop.org/maintainer-tools/committer-drm-misc.html#merge-criteria

As per DRM guidelines, if there are no open comments and the change is
reviewed, it is mergeable.


>
> --
> Best regards,
> Dmitry
>
>