[PATCH 1/2] drm/fb-helper: Don't clobber the display palette when fbdev isn't bound

[PATCH 1/2] drm/fb-helper: Don't clobber the display palette when fbdev isn't bound

[ville.syrjala]

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

Perform the drm_fb_helper_is_bound() check to avoid clobbering the
display palette of some other KMS client.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/drm_fb_helper.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index b78cbe7..1b6ca23 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -626,12 +626,19 @@ static int setcolreg(struct drm_crtc *crtc, u16 red, u16 green,
 int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
 {
 	struct drm_fb_helper *fb_helper = info->par;
+	struct drm_device *dev = fb_helper->dev;
 	struct drm_crtc_helper_funcs *crtc_funcs;
 	u16 *red, *green, *blue, *transp;
 	struct drm_crtc *crtc;
 	int i, j, rc = 0;
 	int start;
 
+	drm_modeset_lock_all(dev);
+	if (!drm_fb_helper_is_bound(fb_helper)) {
+		drm_modeset_unlock_all(dev);
+		return -EBUSY;
+	}
+
 	for (i = 0; i < fb_helper->crtc_count; i++) {
 		crtc = fb_helper->crtc_info[i].mode_set.crtc;
 		crtc_funcs = crtc->helper_private;
@@ -654,10 +661,12 @@ int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
 
 			rc = setcolreg(crtc, hred, hgreen, hblue, start++, info);
 			if (rc)
-				return rc;
+				goto out;
 		}
 		crtc_funcs->load_lut(crtc);
 	}
+ out:
+	drm_modeset_unlock_all(dev);
 	return rc;
 }
 EXPORT_SYMBOL(drm_fb_helper_setcmap);
-- 
1.8.1.5

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[PATCH 2/2] drm/fb-helper: Don't load the display palette if the CRTC is disabled

[ville.syrjala]

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

Often the hardware needs certain clocks running when accessing the
palette, so don't go poking at it if the CRTC is disabled. We still
call the fb_helper gamma_set hooks to update the driver's notion of
what the palette should contain, so that if/when CRTC gets enabled,
the driver will load the correct palette.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
The other option would of course to put the check into the load_lut
function itself. I don't really care which way we do it as long as
the check is somewhere...

 drivers/gpu/drm/drm_fb_helper.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 1b6ca23..4ecf128 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -663,7 +663,9 @@ int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
 			if (rc)
 				goto out;
 		}
-		crtc_funcs->load_lut(crtc);
+
+		if (crtc->enabled)
+			crtc_funcs->load_lut(crtc);
 	}
  out:
 	drm_modeset_unlock_all(dev);
-- 
1.8.1.5

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Re: [PATCH 1/2] drm/fb-helper: Don't clobber the display palette when fbdev isn't bound

[Daniel Vetter]

On Mon, May 27, 2013 at 06:44:56PM +0300, ville.syrjala@linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Perform the drm_fb_helper_is_bound() check to avoid clobbering the
> display palette of some other KMS client.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

You might want to mention that you're also fixing up the locking a bit ;-)
The lack of that would be much more obvious if the fbdev helper would use
the real kms gamma interface instead of it's own driver backdoor. But
that's a different patch to write.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
>  drivers/gpu/drm/drm_fb_helper.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index b78cbe7..1b6ca23 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -626,12 +626,19 @@ static int setcolreg(struct drm_crtc *crtc, u16 red, u16 green,
>  int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
>  {
>  	struct drm_fb_helper *fb_helper = info->par;
> +	struct drm_device *dev = fb_helper->dev;
>  	struct drm_crtc_helper_funcs *crtc_funcs;
>  	u16 *red, *green, *blue, *transp;
>  	struct drm_crtc *crtc;
>  	int i, j, rc = 0;
>  	int start;
>  
> +	drm_modeset_lock_all(dev);
> +	if (!drm_fb_helper_is_bound(fb_helper)) {
> +		drm_modeset_unlock_all(dev);
> +		return -EBUSY;
> +	}
> +
>  	for (i = 0; i < fb_helper->crtc_count; i++) {
>  		crtc = fb_helper->crtc_info[i].mode_set.crtc;
>  		crtc_funcs = crtc->helper_private;
> @@ -654,10 +661,12 @@ int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
>  
>  			rc = setcolreg(crtc, hred, hgreen, hblue, start++, info);
>  			if (rc)
> -				return rc;
> +				goto out;
>  		}
>  		crtc_funcs->load_lut(crtc);
>  	}
> + out:
> +	drm_modeset_unlock_all(dev);
>  	return rc;
>  }
>  EXPORT_SYMBOL(drm_fb_helper_setcmap);
> -- 
> 1.8.1.5
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

Re: [PATCH 2/2] drm/fb-helper: Don't load the display palette if the CRTC is disabled

[Ville Syrjälä]

On Mon, May 27, 2013 at 06:44:57PM +0300, ville.syrjala@linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Often the hardware needs certain clocks running when accessing the
> palette, so don't go poking at it if the CRTC is disabled. We still
> call the fb_helper gamma_set hooks to update the driver's notion of
> what the palette should contain, so that if/when CRTC gets enabled,
> the driver will load the correct palette.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
> The other option would of course to put the check into the load_lut
> function itself. I don't really care which way we do it as long as
> the check is somewhere...

And I just realized we already have the check in i915 load_lut at least.
Not sure how I failed to notice it before. So feel free to ignore this
patch. Patch 1/2 still seems relevant though.

> 
>  drivers/gpu/drm/drm_fb_helper.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 1b6ca23..4ecf128 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -663,7 +663,9 @@ int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
>  			if (rc)
>  				goto out;
>  		}
> -		crtc_funcs->load_lut(crtc);
> +
> +		if (crtc->enabled)
> +			crtc_funcs->load_lut(crtc);
>  	}
>   out:
>  	drm_modeset_unlock_all(dev);
> -- 
> 1.8.1.5

-- 
Ville Syrjälä
Intel OTC

Re: [PATCH 2/2] drm/fb-helper: Don't load the display palette if the CRTC is disabled

[Daniel Vetter]

On Mon, May 27, 2013 at 06:44:57PM +0300, ville.syrjala@linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Often the hardware needs certain clocks running when accessing the
> palette, so don't go poking at it if the CRTC is disabled. We still
> call the fb_helper gamma_set hooks to update the driver's notion of
> what the palette should contain, so that if/when CRTC gets enabled,
> the driver will load the correct palette.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
> The other option would of course to put the check into the load_lut
> function itself. I don't really care which way we do it as long as
> the check is somewhere...
> 
>  drivers/gpu/drm/drm_fb_helper.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 1b6ca23..4ecf128 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -663,7 +663,9 @@ int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
>  			if (rc)
>  				goto out;
>  		}
> -		crtc_funcs->load_lut(crtc);
> +
> +		if (crtc->enabled)

I'd vote for if (crtc->enabled && crtc_funcs->load_lut) since a lot of kms
drivers only implement dummy ->load_lut functions.

Then please also throw a pile of driver patches on top to kill all the now
redundant crtc->enabled checks and all the dummy load_lut functions. With
that fixed this is

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> +			crtc_funcs->load_lut(crtc);
>  	}
>   out:
>  	drm_modeset_unlock_all(dev);
> -- 
> 1.8.1.5
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch