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drm/modes: Allow to specify rotation and reflection on the commandline

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Rotations and reflections setup are needed in some scenarios to initialise
properly the initial framebuffer. Some drivers already had a bunch of
quirks to deal with this, such as either a private kernel command line
parameter (omapdss) or on the device tree (various panels).

In order to accomodate this, let's create a video mode parameter to deal
with the rotation and reflexion.

Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/777da16e42db757c1f5b414b5ca34507097fed5c.1560783090.git-series.maxime.ripard@bootlin.com
This commit is contained in:
Maxime Ripard
2019-06-19 12:17:51 +02:00
parent 3aeeb13d89
commit 1bf4e09227
4 changed files with 146 additions and 20 deletions
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30
drivers/gpu/drm/drm_client_modeset.c
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@@ -824,6 +824,7 @@ bool drm_client_rotation(struct drm_mode_set *modeset, unsigned int *rotation)
{
struct drm_connector *connector = modeset->connectors[0];
struct drm_plane *plane = modeset->crtc->primary;
struct drm_cmdline_mode *cmdline;
u64 valid_mask = 0;
unsigned int i;
@@ -844,6 +845,35 @@ bool drm_client_rotation(struct drm_mode_set *modeset, unsigned int *rotation)
*rotation = DRM_MODE_ROTATE_0;
}
/**
* The panel already defined the default rotation
* through its orientation. Whatever has been provided
* on the command line needs to be added to that.
*
* Unfortunately, the rotations are at different bit
* indices, so the math to add them up are not as
* trivial as they could.
*
* Reflections on the other hand are pretty trivial to deal with, a
* simple XOR between the two handle the addition nicely.
*/
cmdline = &connector->cmdline_mode;
if (cmdline->specified) {
unsigned int cmdline_rest, panel_rest;
unsigned int cmdline_rot, panel_rot;
unsigned int sum_rot, sum_rest;
panel_rot = ilog2(*rotation & DRM_MODE_ROTATE_MASK);
cmdline_rot = ilog2(cmdline->rotation_reflection & DRM_MODE_ROTATE_MASK);
sum_rot = (panel_rot + cmdline_rot) % 4;
panel_rest = *rotation & ~DRM_MODE_ROTATE_MASK;
cmdline_rest = cmdline->rotation_reflection & ~DRM_MODE_ROTATE_MASK;
sum_rest = panel_rest ^ cmdline_rest;
*rotation = (1 << sum_rot) | sum_rest;
}
/*
* TODO: support 90 / 270 degree hardware rotation,
* depending on the hardware this may require the framebuffer