> On 10 Jan 2025, at 12:36 pm, Maxime Ripard <mripard@xxxxxxxxxx> wrote:
>
> Hi,
>
> On Fri, Jan 10, 2025 at 07:44:58AM +0000, Christian Hewitt wrote:
>> Playing YUV420 @ 59.94 media causes HDMI output to lose sync
>> with a fatal error reported:
>>
>> [ 89.610280] Fatal Error, invalid HDMI vclk freq 593406
>>
>> In meson_encoder_hdmi_set_vclk the initial vclk_freq value is
>> 593407 but YUV420 modes halve the value to 296703.5 and this
>> is stored as int which loses precision by rounding down to
>> 296703. The rounded value is later doubled to 593406 and then
>> meson_encoder_hdmi_set_vclk sets an invalid vclk_freq value
>> and the error triggers during meson_vlkc_setup validation.
>>
>> Fix precision in meson_encoder_hdmi_set_vclk by switching to
>> unsigned long long KHz values instead of int MHz. As values
>> for phy_freq are now more accurate we also need to handle an
>> additional match scenario in meson_vclk_setup.
>>
>> Fixes: e5fab2ec9ca4 ("drm/meson: vclk: add support for YUV420 setup")
>> Signed-off-by: Christian Hewitt <christianshewitt@xxxxxxxxx>
>> ---
>> drivers/gpu/drm/meson/meson_encoder_hdmi.c | 42 +++++++++++-----------
>> drivers/gpu/drm/meson/meson_vclk.c | 3 +-
>> 2 files changed, 23 insertions(+), 22 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/meson/meson_encoder_hdmi.c b/drivers/gpu/drm/meson/meson_encoder_hdmi.c
>> index 0593a1cde906..fa37cf975992 100644
>> --- a/drivers/gpu/drm/meson/meson_encoder_hdmi.c
>> +++ b/drivers/gpu/drm/meson/meson_encoder_hdmi.c
>> @@ -70,12 +70,12 @@ static void meson_encoder_hdmi_set_vclk(struct meson_encoder_hdmi *encoder_hdmi,
>> {
>> struct meson_drm *priv = encoder_hdmi->priv;
>> int vic = drm_match_cea_mode(mode);
>> - unsigned int phy_freq;
>> - unsigned int vclk_freq;
>> - unsigned int venc_freq;
>> - unsigned int hdmi_freq;
>> + unsigned long long vclk_freq;
>> + unsigned long long phy_freq;
>> + unsigned long long venc_freq;
>> + unsigned long long hdmi_freq;
>>
>> - vclk_freq = mode->clock;
>> + vclk_freq = mode->clock * 1000ULL;
>
> You should be using drm_hdmi_compute_mode_clock() here
Hello Maxime,
If we’re talking a one-two line change than I’d like pointers
and guidance on how to go about that (offline to avoid group
noise). I have only rudimentary c skills though, so anything
that looks like replumbing a driver around drm_connector is
way beyond my current drm code and general coding knowledge;
I can only offer a fix not a proper improvement :(
Christian
> /* For 420, pixel clock is half unlike venc clock */
>> if (encoder_hdmi->output_bus_fmt == MEDIA_BUS_FMT_UYYVYY8_0_5X24)
>> @@ -85,8 +85,9 @@ static void meson_encoder_hdmi_set_vclk(struct meson_encoder_hdmi *encoder_hdmi,
>> phy_freq = vclk_freq * 10;
>>
>> if (!vic) {
>> - meson_vclk_setup(priv, MESON_VCLK_TARGET_DMT, phy_freq,
>> - vclk_freq, vclk_freq, vclk_freq, false);
>> + meson_vclk_setup(priv, MESON_VCLK_TARGET_DMT, phy_freq / 1000ULL,
>> + vclk_freq / 1000ULL, vclk_freq / 1000ULL,
>> + vclk_freq / 1000ULL, false);
>> return;
>> }
>>
>> @@ -107,12 +108,9 @@ static void meson_encoder_hdmi_set_vclk(struct meson_encoder_hdmi *encoder_hdmi,
>> if (mode->flags & DRM_MODE_FLAG_DBLCLK)
>> venc_freq /= 2;
>>
>> - dev_dbg(priv->dev, "vclk:%d phy=%d venc=%d hdmi=%d enci=%d\n",
>> - phy_freq, vclk_freq, venc_freq, hdmi_freq,
>> - priv->venc.hdmi_use_enci);
>> -
>> - meson_vclk_setup(priv, MESON_VCLK_TARGET_HDMI, phy_freq, vclk_freq,
>> - venc_freq, hdmi_freq, priv->venc.hdmi_use_enci);
>> + meson_vclk_setup(priv, MESON_VCLK_TARGET_HDMI, phy_freq / 1000ULL,
>> + vclk_freq / 1000ULL, venc_freq / 1000ULL, hdmi_freq / 1000ULL,
>> + priv->venc.hdmi_use_enci);
>> }
>>
>> static enum drm_mode_status meson_encoder_hdmi_mode_valid(struct drm_bridge *bridge,
>> @@ -122,10 +120,10 @@ static enum drm_mode_status meson_encoder_hdmi_mode_valid(struct drm_bridge *bri
>> struct meson_encoder_hdmi *encoder_hdmi = bridge_to_meson_encoder_hdmi(bridge);
>> struct meson_drm *priv = encoder_hdmi->priv;
>> bool is_hdmi2_sink = display_info->hdmi.scdc.supported;
>> - unsigned int phy_freq;
>> - unsigned int vclk_freq;
>> - unsigned int venc_freq;
>> - unsigned int hdmi_freq;
>> + unsigned long long vclk_freq;
>> + unsigned long long phy_freq;
>> + unsigned long long venc_freq;
>> + unsigned long long hdmi_freq;
>> int vic = drm_match_cea_mode(mode);
>> enum drm_mode_status status;
>>
>> @@ -149,7 +147,7 @@ static enum drm_mode_status meson_encoder_hdmi_mode_valid(struct drm_bridge *bri
>> } else if (!meson_venc_hdmi_supported_vic(vic))
>> return MODE_BAD;
>>
>> - vclk_freq = mode->clock;
>> + vclk_freq = mode->clock * 1000ULL;
>
> And here too.
>
> Maxime
