Loop N1 instruction delay for burst mode devices are computed
based on horizontal sync and porch timing values.
The current driver is using u16 type for computing this hsync_porch
value, which would failed to fit within the u16 type for large sync
and porch timings devices. This would result in hsync_porch overflow
and eventually computed wrong instruction delay value.
Example, timings, where it produces the overflow
{
.hdisplay = 1080,
.hsync_start = 1080 + 408,
.hsync_end = 1080 + 408 + 4,
.htotal = 1080 + 408 + 4 + 38,
}
It reproduces the desired delay value 65487 but the correct working
value should be 7.
So, Fix it by computing hsync_porch value separately with u32 type.
Fixes: 1c1a7aa366 ("drm/sun4i: dsi: Add burst support")
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190512184128.13720-2-jagan@amarulasolutions.com
The current calculation for the video start delay in the current DSI driver
is that it is the total vertical size, minus the front porch and sync length,
plus 1. This equals to the active vertical size plus the back porch plus 1.
That 1 is coming in the Allwinner BSP from an variable that is set to 1.
However, if we look at the Allwinner BSP more closely, and especially in
the "legacy" code for the display (in drivers/video/sunxi/legacy/), we can
see that this variable is actually computed from the porches and the sync
minus 10, clamped between 8 and 100.
This fixes the start delay symptom we've seen on some panels (vblank
timeouts with vertical white stripes at the bottom of the panel).
Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/6e5f72e68f47ca0223877464bf12f0c3f3978de8.1549896081.git-series.maxime.ripard@bootlin.com
Right now, the DRM panel logic returns NULL when a panel pointing to
the passed OF node is not present in the list of registered panels.
Most drivers interpret this NULL value as -EPROBE_DEFER, but we are
about to modify the semantic of of_drm_find_panel() and let the
framework return -ENODEV when the device node we're pointing to has
a status property that is not equal to "okay" or "ok".
Let's first patch the of_drm_find_panel() implementation to return
ERR_PTR(-EPROBE_DEFER) instead of NULL and patch all callers to replace
the '!panel' check by an 'IS_ERR(panel)' one.
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180509130042.9435-2-boris.brezillon@bootlin.com
Disabling CONFIG_PM produces a compile time warning when these
functions are not referenced:
drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c:1072:12: error: 'sun6i_dsi_runtime_suspend' defined but not used [-Werror=unused-function]
static int sun6i_dsi_runtime_suspend(struct device *dev)
^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c:1043:12: error: 'sun6i_dsi_runtime_resume' defined but not used [-Werror=unused-function]
static int sun6i_dsi_runtime_resume(struct device *dev)
^~~~~~~~~~~~~~~~~~~~~~~~
Fixes: 133add5b5a ("drm/sun4i: Add Allwinner A31 MIPI-DSI controller support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180525155030.3667352-1-arnd@arndb.de
