diff options
| author | Jagan Teki <jagan@amarulasolutions.com> | 2019-05-13 00:11:26 +0530 |
|---|---|---|
| committer | Maxime Ripard <maxime.ripard@bootlin.com> | 2019-05-16 10:59:19 +0200 |
| commit | 51a0d1a90bff5d90a1a1c58e165928a0dd92268a (patch) | |
| tree | fe84c113cece4fd808bbaa9301b524691aabcca5 | |
| parent | 831adffb3b7b8df4c8e20b7b00843129fb87a166 (diff) | |
drm/sun4i: sun6i_mipi_dsi: Fix hsync_porch overflowdrm-misc-next-fixes-2019-05-20
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: 1c1a7aa3663c ("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
| -rw-r--r-- | drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c index 6ff585055a07..bfa7e2b146df 100644 --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c @@ -457,8 +457,9 @@ static void sun6i_dsi_setup_inst_loop(struct sun6i_dsi *dsi, u16 delay = 50 - 1; if (device->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) { - delay = (mode->htotal - mode->hdisplay) * 150; - delay /= (mode->clock / 1000) * 8; + u32 hsync_porch = (mode->htotal - mode->hdisplay) * 150; + + delay = (hsync_porch / ((mode->clock / 1000) * 8)); delay -= 50; } |