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Commit d42986b6 authored by Fabio Estevam's avatar Fabio Estevam Committed by Dave Airlie
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drm: mxsfb_crtc: Fix the framebuffer misplacement



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: default avatarBreno Lima <breno.lima@nxp.com>
Signed-off-by: default avatarFabio Estevam <fabio.estevam@nxp.com>
Tested-by: default avatarBreno Lima <breno.lima@nxp.com>
Tested-by: default avatarMarek Vasut <marex@denx.de>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 7ad7a5ac
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