Hi,
The Allwinner display engine doesn't have any kind of hardware help to deal with TV overscan.
This means that if we use the only mode the hardware provides (either PAL or NTSC, or something else), most of the screens will crop the borders of the image, which is bad.
We can however use somekind of a hack, to instead reduce the mode exposed to the userspace, and center it in the final image. We would expose different overscan ratio to be able to deal with most of the screens, each reducing more the displayable area.
The first patches are rework for the command line parser in order to be able to use named modes. This is going to be helpful for us, since different modes might have the same timings but only differ on a few settings not exposed in the modes, but it might eventually be used for the *VGA modes for example.
The last patches extend the current driver to deal with the changes used to introduce the overscan.
Let me know what you think, Maxime
Maxime Ripard (5): drm/modes: Rewrite the command line parser drm/modes: Support modes names on the command line drm/sun4i: Add custom crtc state drm/sun4i: Compute TCON1 mode from tv mode drm/sun4i: Add support for the overscan profiles
drivers/gpu/drm/drm_connector.c | 3 +- drivers/gpu/drm/drm_fb_helper.c | 4 +- drivers/gpu/drm/drm_modes.c | 324 +++++++++++++++++---------- drivers/gpu/drm/sun4i/sun4i_backend.c | 18 +- drivers/gpu/drm/sun4i/sun4i_crtc.c | 37 ++- drivers/gpu/drm/sun4i/sun4i_crtc.h | 16 +- drivers/gpu/drm/sun4i/sun4i_rgb.c | 10 +- drivers/gpu/drm/sun4i/sun4i_tv.c | 75 ++++-- include/drm/drm_connector.h | 1 +- 9 files changed, 342 insertions(+), 146 deletions(-)