Re: [PATCH 3/3] drm/client: log: Implement struct drm_client_funcs.restore

Jocelyn Falempe
2025-11-10T14:05:23Z

On 07/11/2025 15:19, Thomas Zimmermann wrote:
> Restore the log client's output when the DRM core invokes the restore
> callback. Follow the existing behavior of fbdev emulation wrt. the
> value of the force parameter.
>
> If force is false, acquire the DRM master lock and reprogram the
> display. This is the case when the user-space compositor exists and
> the DRM core transfers the display back to the in-kernel client. This
> also enables log output during reboots.
>
> If force is true, reprogram without considering the master lock. This
> overrides the current compositor and prints the log to the screen. In
> case of system malfunction, users can enter SysRq+v to invoke the
> emergency error reporting. See Documentation/admin-guide/sysrq.rst for
> more information.

Thanks, it looks good to me.

Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>

>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
> drivers/gpu/drm/clients/drm_log.c | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/drivers/gpu/drm/clients/drm_log.c b/drivers/gpu/drm/clients/drm_log.c
> index 19e55aa0ed74..4d3005273b27 100644
> --- a/drivers/gpu/drm/clients/drm_log.c
> +++ b/drivers/gpu/drm/clients/drm_log.c
> @@ -315,6 +315,18 @@ static void drm_log_client_unregister(struct drm_client_dev *client)
> drm_client_release(client);
> }
>
> +static int drm_log_client_restore(struct drm_client_dev *client, bool force)
> +{
> + int ret;
> +
> + if (force)
> + ret = drm_client_modeset_commit_locked(client);
> + else
> + ret = drm_client_modeset_commit(client);
> +
> + return ret;
> +}
> +
> static int drm_log_client_hotplug(struct drm_client_dev *client)
> {
> struct drm_log *dlog = client_to_drm_log(client);
> @@ -348,6 +360,7 @@ static const struct drm_client_funcs drm_log_client_funcs = {
> .owner = THIS_MODULE,
> .free = drm_log_client_free,
> .unregister = drm_log_client_unregister,
> + .restore = drm_log_client_restore,
> .hotplug = drm_log_client_hotplug,
> .suspend = drm_log_client_suspend,
> .resume = drm_log_client_resume,