[PATCH] drm: Lighten sysfs connector 'status'

[Alex Deucher]

On Fri, Mar 6, 2015 at 7:36 AM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> Since the beginning, sysfs/connector/status has done a heavyweight
> detection of the current connector status. But no user, such as upowerd
> or logind, has ever desired to initiate a probe. Move the probing into a
> new attribute so that existing readers get the behaviour they desire.
>
> v2: David Herrmann suggested using "echo detect > /sys/.../status" to
> trigger the probing, which is a fine idea. This extends that to also
> allow the user to apply the force detection overrides at runtime.
>
> v3: Now with airlied's email address fixed! Requires sysfs_streq()
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: David Herrmann <dh.herrmann at gmail.com>
> Cc: Dave Airlie <airlied at redhat.com>
> Cc: Alex Deucher <alexdeucher at gmail.com>

Reviewed-by: Alex Deucher <alexander.deucher at amd.com>

> ---
>  drivers/gpu/drm/drm_sysfs.c | 61 +++++++++++++++++++++++++++++++++++++++------
>  1 file changed, 53 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
> index 5c99d3773212..ffc305fc2076 100644
> --- a/drivers/gpu/drm/drm_sysfs.c
> +++ b/drivers/gpu/drm/drm_sysfs.c
> @@ -166,23 +166,68 @@ void drm_sysfs_destroy(void)
>  /*
>   * Connector properties
>   */
> -static ssize_t status_show(struct device *device,
> +static ssize_t status_store(struct device *device,
>                            struct device_attribute *attr,
> -                          char *buf)
> +                          const char *buf, size_t count)
>  {
>         struct drm_connector *connector = to_drm_connector(device);
> -       enum drm_connector_status status;
> +       struct drm_device *dev = connector->dev;
> +       enum drm_connector_status old_status;
>         int ret;
>
> -       ret = mutex_lock_interruptible(&connector->dev->mode_config.mutex);
> +       ret = mutex_lock_interruptible(&dev->mode_config.mutex);
>         if (ret)
>                 return ret;
>
> -       status = connector->funcs->detect(connector, true);
> -       mutex_unlock(&connector->dev->mode_config.mutex);
> +       old_status = connector->status;
> +
> +       if (sysfs_streq(buf, "detect")) {
> +               connector->force = 0;
> +               connector->status = connector->funcs->detect(connector, true);
> +       } else if (sysfs_streq(buf, "on")) {
> +               connector->force = DRM_FORCE_ON;
> +       } else if (sysfs_streq(buf, "on-digital")) {
> +               connector->force = DRM_FORCE_ON_DIGITAL;
> +       } else if (sysfs_streq(buf, "off")) {
> +               connector->force = DRM_FORCE_OFF;
> +       } else
> +               ret = -EINVAL;
> +
> +       if (ret == 0 && connector->force) {
> +               if (connector->force == DRM_FORCE_ON ||
> +                   connector->force == DRM_FORCE_ON_DIGITAL)
> +                       connector->status = connector_status_connected;
> +               else
> +                       connector->status = connector_status_disconnected;
> +               if (connector->funcs->force)
> +                       connector->funcs->force(connector);
> +       }
> +
> +       if (old_status != connector->status) {
> +               DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %d to %d\n",
> +                             connector->base.id,
> +                             connector->name,
> +                             old_status, connector->status);
> +
> +               dev->mode_config.delayed_event = true;
> +               if (dev->mode_config.poll_enabled)
> +                       schedule_delayed_work(&dev->mode_config.output_poll_work,
> +                                             0);
> +       }
> +
> +       mutex_unlock(&dev->mode_config.mutex);
> +
> +       return ret;
> +}
> +
> +static ssize_t status_show(struct device *device,
> +                          struct device_attribute *attr,
> +                          char *buf)
> +{
> +       struct drm_connector *connector = to_drm_connector(device);
>
>         return snprintf(buf, PAGE_SIZE, "%s\n",
> -                       drm_get_connector_status_name(status));
> +                       drm_get_connector_status_name(connector->status));
>  }
>
>  static ssize_t dpms_show(struct device *device,
> @@ -339,7 +384,7 @@ static ssize_t select_subconnector_show(struct device *device,
>                         drm_get_dvi_i_select_name((int)subconnector));
>  }
>
> -static DEVICE_ATTR_RO(status);
> +static DEVICE_ATTR_RW(status);
>  static DEVICE_ATTR_RO(enabled);
>  static DEVICE_ATTR_RO(dpms);
>  static DEVICE_ATTR_RO(modes);
> --
> 2.1.4
>