Playing 4K media with 59.94 fractional rate (typically VP9) causes the screen to lose
sync with the following error reported in the system log:
[ 89.610280] Fatal Error, invalid HDMI vclk freq 593406
Modetest shows the following:
3840x2160 59.94 3840 4016 4104 4400 2160 2168 2178 2250 593407 flags: xxxx, xxxx,
drm calculated value -------------------------------------^
Change the fractional rate calculation to stop DIV_ROUND_CLOSEST rounding down which
results in vclk freq failing to match correctly.
Fixes: e5fab2ec9ca4 ("drm/meson: vclk: add support for YUV420 setup")
Signed-off-by: Christian Hewitt <christianshewitt@xxxxxxxxx>
---
I'm unable to give a better mathematical description of the fix as I can barely read
code. The change was inspired by [0] which I chanced upon while looking at how other
dw-hdmi drivers handle fractional rates.
[0] https://github.com/torvalds/linux/commit/4f510aa10468954b1da4e94689c38ac6ea8d3627
drivers/gpu/drm/meson/meson_vclk.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/meson/meson_vclk.c b/drivers/gpu/drm/meson/meson_vclk.c
index 2a82119eb58e..2a942dc6a6dc 100644
--- a/drivers/gpu/drm/meson/meson_vclk.c
+++ b/drivers/gpu/drm/meson/meson_vclk.c
@@ -790,13 +790,13 @@ meson_vclk_vic_supported_freq(struct meson_drm *priv, unsigned int phy_freq,
FREQ_1000_1001(params[i].pixel_freq));
DRM_DEBUG_DRIVER("i = %d phy_freq = %d alt = %d\n",
i, params[i].phy_freq,
- FREQ_1000_1001(params[i].phy_freq/10)*10);
+ FREQ_1000_1001(params[i].phy_freq/1000)*1000);
/* Match strict frequency */
if (phy_freq == params[i].phy_freq &&
vclk_freq == params[i].vclk_freq)
return MODE_OK;
/* Match 1000/1001 variant */
- if (phy_freq == (FREQ_1000_1001(params[i].phy_freq/10)*10) &&
+ if (phy_freq == (FREQ_1000_1001(params[i].phy_freq/1000)*1000) &&
vclk_freq == FREQ_1000_1001(params[i].vclk_freq))
return MODE_OK;
}
@@ -1070,7 +1070,7 @@ void meson_vclk_setup(struct meson_drm *priv, unsigned int target,
for (freq = 0 ; params[freq].pixel_freq ; ++freq) {
if ((phy_freq == params[freq].phy_freq ||
- phy_freq == FREQ_1000_1001(params[freq].phy_freq/10)*10) &&
+ phy_freq == FREQ_1000_1001(params[freq].phy_freq/1000)*1000) &&
(vclk_freq == params[freq].vclk_freq ||
vclk_freq == FREQ_1000_1001(params[freq].vclk_freq))) {
if (vclk_freq != params[freq].vclk_freq)
--
2.34.1
