Re: [v5,13/13] drm/ast: Automatically clean up poll helper

[Thomas Zimmermann <tzimmermann@xxxxxxx>]

Hi

Am 21.03.24 um 10:00 schrieb Sui Jingfeng:
> Hi,
>
>
> On 2024/3/20 17:34, Thomas Zimmermann wrote:
> > Automatically clean up the conncetor-poll thread as part of the DRM
> > device release. The new helper drmm_kms_helper_poll_init() provides
> > a shared implementation for all drivers.
> >
> > Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
>
>
> Nice feature!
>
> It seems that drm/loongson forget to calldrm_kms_helper_poll_fini() on 
> driver leave, Opps.

Indeed. I'm surprised that this never blew up with ast. Without _fini(), 
the polling thread would likely run on a stale DRM device. We only 
release the device during shutdown and I guess it doesn't make 
difference then.

Best regards
Thomas

> Acked-by: Sui Jingfeng <sui.jingfeng@xxxxxxxxx>
>
>
>
> > ---
> >   drivers/gpu/drm/ast/ast_mode.c     |  4 +++-
> >   drivers/gpu/drm/drm_probe_helper.c | 27 +++++++++++++++++++++++++++
> >   include/drm/drm_probe_helper.h     |  2 ++
> >   3 files changed, 32 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/ast/ast_mode.c 
> > b/drivers/gpu/drm/ast/ast_mode.c
> > index a42a0956c51de..7e56a77bed635 100644
> > --- a/drivers/gpu/drm/ast/ast_mode.c
> > +++ b/drivers/gpu/drm/ast/ast_mode.c
> > @@ -1905,7 +1905,9 @@ int ast_mode_config_init(struct ast_device *ast)
> >         drm_mode_config_reset(dev);
> >   -    drm_kms_helper_poll_init(dev);
> > +    ret = drmm_kms_helper_poll_init(dev);
> > +    if (ret)
> > +        return ret;
> >         return 0;
> >   }
> > diff --git a/drivers/gpu/drm/drm_probe_helper.c 
> > b/drivers/gpu/drm/drm_probe_helper.c
> > index b06dcc6c614e8..a39c98ceac68a 100644
> > --- a/drivers/gpu/drm/drm_probe_helper.c
> > +++ b/drivers/gpu/drm/drm_probe_helper.c
> > @@ -37,6 +37,7 @@
> >   #include <drm/drm_crtc.h>
> >   #include <drm/drm_edid.h>
> >   #include <drm/drm_fourcc.h>
> > +#include <drm/drm_managed.h>
> >   #include <drm/drm_modeset_helper_vtables.h>
> >   #include <drm/drm_print.h>
> >   #include <drm/drm_probe_helper.h>
> > @@ -944,6 +945,32 @@ void drm_kms_helper_poll_fini(struct drm_device 
> > *dev)
> >   }
> >   EXPORT_SYMBOL(drm_kms_helper_poll_fini);
> >   +static void drm_kms_helper_poll_init_release(struct drm_device 
> > *dev, void *res)
> > +{
> > +    drm_kms_helper_poll_fini(dev);
> > +}
> > +
> > +/**
> > + * devm_drm_kms_helper_poll_init - initialize and enable output polling
> > + * @dev: drm_device
> > + *
> > + * This function initializes and then also enables output polling 
> > support for
> > + * @dev similar to drm_kms_helper_poll_init(). Polling will 
> > automatically be
> > + * cleaned up when the DRM device goes away.
> > + *
> > + * See drm_kms_helper_poll_init() for more information.
> > + *
> > + * Returns:
> > + * 0 on success, or a negative errno code otherwise.
> > + */
> > +int drmm_kms_helper_poll_init(struct drm_device *dev)
> > +{
> > +    drm_kms_helper_poll_init(dev);
> > +
> > +    return drmm_add_action_or_reset(dev, 
> > drm_kms_helper_poll_init_release, dev);
> > +}
> > +EXPORT_SYMBOL(drmm_kms_helper_poll_init);
> > +
> >   static bool check_connector_changed(struct drm_connector *connector)
> >   {
> >       struct drm_device *dev = connector->dev;
> > diff --git a/include/drm/drm_probe_helper.h 
> > b/include/drm/drm_probe_helper.h
> > index 031b044528c89..9925cff749296 100644
> > --- a/include/drm/drm_probe_helper.h
> > +++ b/include/drm/drm_probe_helper.h
> > @@ -16,6 +16,8 @@ int drm_helper_probe_single_connector_modes(struct 
> > drm_connector
> >   int drm_helper_probe_detect(struct drm_connector *connector,
> >                   struct drm_modeset_acquire_ctx *ctx,
> >                   bool force);
> > +
> > +int drmm_kms_helper_poll_init(struct drm_device *dev);
> >   void drm_kms_helper_poll_init(struct drm_device *dev);
> >   void drm_kms_helper_poll_fini(struct drm_device *dev);
> >   bool drm_helper_hpd_irq_event(struct drm_device *dev);

--
--
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)