Re: [PATCH] drm: exynos: Fix fb_videomode <-> drm_mode_modeinfo conversion

On 03/08/2012 08:34 PM, Laurent Pinchart wrote:

The fb_videomode structure stores the front porch and back porch in the right_margin and left_margin fields respectively. right_margin should thus be computed with hsync_start - hdisplay, and left_margin with htotal - hsync_end. The same holds for the vertical direction.

    Active               Front           Sync            Back
    Region               Porch                           Porch

<-------------------><----------------><-------------><---------------->

//////////////////| ////////////////// | ////////////////// |.................. .................. _______________

<------ xres -------><- right_margin -><- hsync_len -><- left_margin -->

<---- hdisplay -----> <------------ hsync_start ------------> <--------------------- hsync_end --------------------> <--------------------------------- htotal ----------------------------->

Fix the fb_videomode<-> drm_mode_modeinfo conversion functions accordingly.

Signed-off-by: Laurent Pinchartlaurent.pinchart@ideasonboard.com

drivers/gpu/drm/exynos/exynos_drm_connector.c | 16 ++++++++-------- 1 files changed, 8 insertions(+), 8 deletions(-)

While trying to understand how the fb_videomode and drm_mode_modeinfo fields map to each other, I found what might be a bug in the Exynos DRM driver. Could you please check and confirm that my understanding is correct ?

Good catch. You can refer Documentation/fb/framebuffer.txt to know in detail.

Acked-by: Joonyoung Shim jy0922.shim@samsung.com

Thanks.

diff --git a/drivers/gpu/drm/exynos/exynos_drm_connector.c b/drivers/gpu/drm/exynos/exynos_drm_connector.c index d620b07..7bb1dca 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_connector.c +++ b/drivers/gpu/drm/exynos/exynos_drm_connector.c @@ -52,14 +52,14 @@ convert_to_display_mode(struct drm_display_mode *mode, mode->vrefresh = timing->refresh;

mode->hdisplay = timing->xres;

• mode->hsync_start = mode->hdisplay + timing->left_margin;

• mode->hsync_start = mode->hdisplay + timing->right_margin; mode->hsync_end = mode->hsync_start + timing->hsync_len;

• mode->htotal = mode->hsync_end + timing->right_margin;

• mode->htotal = mode->hsync_end + timing->left_margin;

  mode->vdisplay = timing->yres;

• mode->vsync_start = mode->vdisplay + timing->upper_margin;

• mode->vsync_start = mode->vdisplay + timing->lower_margin; mode->vsync_end = mode->vsync_start + timing->vsync_len;

• mode->vtotal = mode->vsync_end + timing->lower_margin;

• mode->vtotal = mode->vsync_end + timing->upper_margin;

  if (timing->vmode& FB_VMODE_INTERLACED) mode->flags |= DRM_MODE_FLAG_INTERLACE;

@@ -81,14 +81,14 @@ convert_to_video_timing(struct fb_videomode *timing, timing->refresh = drm_mode_vrefresh(mode);

timing->xres = mode->hdisplay;

• timing->left_margin = mode->hsync_start - mode->hdisplay;

• timing->right_margin = mode->hsync_start - mode->hdisplay; timing->hsync_len = mode->hsync_end - mode->hsync_start;

• timing->right_margin = mode->htotal - mode->hsync_end;

• timing->left_margin = mode->htotal - mode->hsync_end;

  timing->yres = mode->vdisplay;

• timing->upper_margin = mode->vsync_start - mode->vdisplay;

• timing->lower_margin = mode->vsync_start - mode->vdisplay; timing->vsync_len = mode->vsync_end - mode->vsync_start;

• timing->lower_margin = mode->vtotal - mode->vsync_end;

• timing->upper_margin = mode->vtotal - mode->vsync_end;

  if (mode->flags& DRM_MODE_FLAG_INTERLACE) timing->vmode = FB_VMODE_INTERLACED;