[PATCH] drm: mxsfb_crtc: Fix the framebuffer misplacement

[Marek Vasut]

On 02/02/2017 10:26 PM, Fabio Estevam wrote:
> From: Fabio Estevam <fabio.estevam at nxp.com>
> 
> Currently the framebuffer content is displayed with incorrect offsets
> in both the vertical and horizontal directions.
> 
> The fbdev version of the driver does not show this problem. Breno Lima
> dumped the eLCDIF controller registers on both the drm and fbdev drivers
> and noticed that the VDCTRL3 register is configured incorrectly in the
> drm driver.
> 
> The fbdev driver calculates the vertical and horizontal wait counts
> of the VDCTRL3 register by doing: back porch + sync length.
> 
> Looking at the horizontal and vertical timing diagram from 
> include/drm/drm_modes.h this value corresponds to:
> 
> crtc_[hv]total - crtc_[hv]sync_start
> 
> So fix the VDCTRL3 register setting accordingly so that the eLCDIF
> controller can properly show the framebuffer content in the correct
> position.
> 
> Reported-by: Breno Lima <breno.lima at nxp.com>
> Signed-off-by: Fabio Estevam <fabio.estevam at nxp.com>

Tested-by: Marek Vasut <marex at denx.de>

-- 
Best regards,
Marek Vasut