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[v3,2/2] drm/fb-helper: pass physical dimensions to fbdev

Message ID 1501777149-8310-3-git-send-email-david@lechnology.com (mailing list archive)
State New, archived
Headers show

Commit Message

David Lechner Aug. 3, 2017, 4:19 p.m. UTC
The fbdev subsystem has a place for physical dimensions (width and height
in mm) that is readable by userspace. Since DRM also knows these
dimensions, pass this information to the fbdev device.

This has to be done in drm_setup_crtcs_fb() instead of drm_setup_crtcs()
because fb_helper->fbdev may be NULL in drm_setup_crtcs().

Signed-off-by: David Lechner <david@lechnology.com>
---
 drivers/gpu/drm/drm_fb_helper.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

Comments

Daniel Vetter Aug. 4, 2017, 8:58 a.m. UTC | #1
On Thu, Aug 03, 2017 at 11:19:09AM -0500, David Lechner wrote:
> The fbdev subsystem has a place for physical dimensions (width and height
> in mm) that is readable by userspace. Since DRM also knows these
> dimensions, pass this information to the fbdev device.
> 
> This has to be done in drm_setup_crtcs_fb() instead of drm_setup_crtcs()
> because fb_helper->fbdev may be NULL in drm_setup_crtcs().
> 
> Signed-off-by: David Lechner <david@lechnology.com>
> ---
>  drivers/gpu/drm/drm_fb_helper.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 24a721a..a98bf86 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -1882,8 +1882,6 @@ void drm_fb_helper_fill_var(struct fb_info *info, struct drm_fb_helper *fb_helpe
>  	info->var.xoffset = 0;
>  	info->var.yoffset = 0;
>  	info->var.activate = FB_ACTIVATE_NOW;
> -	info->var.height = -1;
> -	info->var.width = -1;
>  
>  	switch (fb->format->depth) {
>  	case 8:
> @@ -2435,11 +2433,24 @@ static void drm_setup_crtcs(struct drm_fb_helper *fb_helper,
>   */
>  static void drm_setup_crtcs_fb(struct drm_fb_helper *fb_helper)
>  {
> +	struct fb_info *info = fb_helper->fbdev;
>  	int i;
>  
>  	for (i = 0; i < fb_helper->crtc_count; i++)
>  		if (fb_helper->crtc_info[i].mode_set.num_connectors)
>  			fb_helper->crtc_info[i].mode_set.fb = fb_helper->fb;
> +
> +	drm_fb_helper_for_each_connector(fb_helper, i) {
> +		struct drm_connector *connector =
> +					fb_helper->connector_info[i]->connector;
> +
> +		/* use first connected connector for the physical dimensions */
> +		if (connector->status == connector_status_connected) {
> +			info->var.height = connector->display_info.width_mm;
> +			info->var.width = connector->display_info.height_mm;
> +			break;
> +		}
> +	}

Ok, small trapdoor I didn't highlight: Accessing the connector prope state
(i.e. ->status and ->display_info) requires that you hold
dev->mode_config.mutex. See how it's done in drm_setup_crtcs, just wrap it
around this loop here.

fbdev state itself is protected by fb_helper->lock, so that part is all
good.

I've applied patch 1 already, but can you pls respin that one with the
locking fixed up?

Thanks, Daniel
>  }
>  
>  /* Note: Drops fb_helper->lock before returning. */
> -- 
> 2.7.4
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
diff mbox

Patch

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 24a721a..a98bf86 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1882,8 +1882,6 @@  void drm_fb_helper_fill_var(struct fb_info *info, struct drm_fb_helper *fb_helpe
 	info->var.xoffset = 0;
 	info->var.yoffset = 0;
 	info->var.activate = FB_ACTIVATE_NOW;
-	info->var.height = -1;
-	info->var.width = -1;
 
 	switch (fb->format->depth) {
 	case 8:
@@ -2435,11 +2433,24 @@  static void drm_setup_crtcs(struct drm_fb_helper *fb_helper,
  */
 static void drm_setup_crtcs_fb(struct drm_fb_helper *fb_helper)
 {
+	struct fb_info *info = fb_helper->fbdev;
 	int i;
 
 	for (i = 0; i < fb_helper->crtc_count; i++)
 		if (fb_helper->crtc_info[i].mode_set.num_connectors)
 			fb_helper->crtc_info[i].mode_set.fb = fb_helper->fb;
+
+	drm_fb_helper_for_each_connector(fb_helper, i) {
+		struct drm_connector *connector =
+					fb_helper->connector_info[i]->connector;
+
+		/* use first connected connector for the physical dimensions */
+		if (connector->status == connector_status_connected) {
+			info->var.height = connector->display_info.width_mm;
+			info->var.width = connector->display_info.height_mm;
+			break;
+		}
+	}
 }
 
 /* Note: Drops fb_helper->lock before returning. */