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

[Inki Dae]

Hi Laurent,

> -----Original Message-----
> From: Joonyoung Shim [mailto:jy0922.shim at samsung.com]
> Sent: Thursday, March 08, 2012 10:06 PM
> To: Laurent Pinchart
> Cc: dri-devel at lists.freedesktop.org; linux-fbdev at vger.kernel.org; Inki
Dae;
> Seung-Woo Kim; Kyungmin Park
> Subject: 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 Pinchart<laurent.pinchart at 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 at samsung.com>
> 
> Thanks.
> 

it seems like that you doesn't use latest exynos drm driver so I merged it
manually
for this, you can refer to this link:
http://git.infradead.org/users/kmpark/linux-samsung/shortlog/refs/heads/exyn
os-drm-fixes

Thanks,
Inki Dae

> > 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;