DRM accel and debugfs/sysfs

[Daniel Vetter]

On Tue, Feb 07, 2023 at 01:17:47PM -0300, Maíra Canal wrote:
> On 2/7/23 12:43, Jeffrey Hugo wrote:
> > On 2/7/2023 4:31 AM, Maíra Canal wrote:
> > > Hi Stanislaw,
> > > 
> > > On 2/1/23 12:20, Stanislaw Gruszka wrote:
> > > > Hi
> > > > 
> > > > I was about to send debugfs support for ivpu and noticed that there
> > > > are current changes that deprecate drm_devel->debugfs_init callback.
> > > > 
> > > > Further I looked at this commit [1], that stated we should not
> > > > use drm_minor for debugfs and sysfs. What is quite contrary to
> > > > what drm accel framework did in the first place.
> > > > 
> > > > So my question is how we should use debugfs/sysfs in accel?
> > > > Use it with old fashioned minor-centric way or change
> > > > the framework somehow ?
> > > 
> > > As we are trying to replace drm_debugfs_create_files() [1], it would
> > > be nice to see the accel debugfs support use the new debugfs API. This
> > > would mean using the debugfs_list from the drm_device, deprecating
> > > the debugfs_init callback, and adding the a similar code snippet to
> > > accel_debugfs_init:
> > > 
> > > list_for_each_entry_safe(entry, tmp, &dev->debugfs_list, list) {
> > >      debugfs_create_file(entry->file.name, 0444,
> > >                  minor->debugfs_root, entry, &drm_debugfs_entry_fops);
> > >      list_del(&entry->list);
> > > 
> > > Maybe Daniel has some more thoughts on this matter, but I guess it
> > > would be better to drop the use of the old-fashioned minor-centric
> > > implementation in accel.

It was a simple case of two things landing in parallel and not being
synchronized. Would be good if accel could be adapted to use the new
debugfs infra, now that both accel and the new debugfs stuff have landed.
-Daniel

> > > 
> > > [1] https://cgit.freedesktop.org/drm/drm-misc/tree/Documentation/gpu/todo.rst#n511
> > > 
> > > Best Regards,
> > > - Maíra Canal
> > 
> > Thank you for the details Maira.  It helps to explain what the todo is suggesting.  Is there an example of a driver/drm_device that uses debugfs_list which you can easily point to?
> 
> The implementation of this device-centered infrastructure is linked in [1]
> and an example of the conversion of debugfs APIs is linked in [2], and other
> drivers such as v3d, vkms, vc4 and gud use this new API as well.
> 
> [1] https://cgit.freedesktop.org/drm/drm-misc/commit/?id=1c9cacbea880513a896aee65a5c58007bcb55653
> [2] https://cgit.freedesktop.org/drm/drm-misc/commit/?id=2e3ab8a6994f265bbd4dbd00448b84548f18464c
> 
> Best Regards,
> - Maíra Canal
> 
> > 
> > -Jeff
> > 
> > > 
> > > > 
> > > > [1] https://cgit.freedesktop.org/drm/drm-misc/commit/?id=99845faae7099cd704ebf67514c1157c26960a26
> > > > 
> > > > Regards
> > > > Stanislaw
> > > > 
> > 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch