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drm/sun4i: rgb: Validate the clock rate 

Our pixel clock cannot reach a high enough rate for some rather high while
common resolutions (like 1080p60).

Make sure we filter the resolutions we cannot reach in our mode_valid
function.

Fixes: 29e57fab97 ("drm: sun4i: Add RGB output")
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
This commit is contained in:
Maxime Ripard 2016-04-21 11:25:26 +02:00
parent 4731a72df2
commit bb43d40d7c
1 changed files with 14 additions and 0 deletions
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14
drivers/gpu/drm/sun4i/sun4i_rgb.c
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@ -54,8 +54,13 @@ static int sun4i_rgb_get_modes(struct drm_connector *connector)
static int sun4i_rgb_mode_valid(struct drm_connector *connector,
struct drm_display_mode *mode)
{
struct sun4i_rgb *rgb = drm_connector_to_sun4i_rgb(connector);
struct sun4i_drv *drv = rgb->drv;
struct sun4i_tcon *tcon = drv->tcon;
u32 hsync = mode->hsync_end - mode->hsync_start;
u32 vsync = mode->vsync_end - mode->vsync_start;
unsigned long rate = mode->clock * 1000;
long rounded_rate;
DRM_DEBUG_DRIVER("Validating modes...\n");
@ -87,6 +92,15 @@ static int sun4i_rgb_mode_valid(struct drm_connector *connector,
DRM_DEBUG_DRIVER("Vertical parameters OK\n");
rounded_rate = clk_round_rate(tcon->dclk, rate);
if (rounded_rate < rate)
return MODE_CLOCK_LOW;
if (rounded_rate > rate)
return MODE_CLOCK_HIGH;
DRM_DEBUG_DRIVER("Clock rate OK\n");
return MODE_OK;
}