[PATCH v2 2/3] video: rockchip: rk3328: filter unsupported modes

[Vasily Khoruzhick]

On Sun, Mar 23, 2025, 22:36 Matwey V. Kornilov <matwey.kornilov at gmail.com>
wrote:

> You say that the 4K works in Linux. Wouldn't it be better to fix the 4K
> support in u-boot?
>

Hey Matwey,

A proper fix would certainly be better, however I don't really have neither
time nor motivation to debug it further.

We can either leave it broken as it is now and wait for someone else to fix
it or plug it with a workaround for a time being.

I'd be happy to test the fix if you volunteer to debug it.

Regards,
Vasily

пн, 24 мар. 2025 г., 01:51 Vasily Khoruzhick <anarsoul at gmail.com>:
>
>> While RK3328 is capable of 4K resolutions, dw-hdmi driver in u-boot
>> seems to have some issue with 4K. 1440p or lower works fine.
>>
>> Limit max resolutions to 2560x1440x60Hz, by filtering the modes with
>> pixel clock > 297MHz
>>
>> Fixes: f3ea872970d603 ("video: rockchip: Add rk3328 hdmi support")
>> Signed-off-by: Vasily Khoruzhick <anarsoul at gmail.com>
>> ---
>> v2: add a comment that max pixel clock limit is a workaround
>>
>> drivers/video/rockchip/rk3328_hdmi.c | 11 +++++++++++
>>  1 file changed, 11 insertions(+)
>>
>> diff --git a/drivers/video/rockchip/rk3328_hdmi.c
>> b/drivers/video/rockchip/rk3328_hdmi.c
>> index 763669c09be..ff351aaac7c 100644
>> --- a/drivers/video/rockchip/rk3328_hdmi.c
>> +++ b/drivers/video/rockchip/rk3328_hdmi.c
>> @@ -105,9 +105,20 @@ static int rk3328_hdmi_probe(struct udevice *dev)
>>         return 0;
>>  }
>>
>> +static bool rk3328_hdmi_mode_valid(struct udevice *dev,
>> +                                  const struct display_timing *timing)
>> +{
>> +       /* Limit pixel clock to 297MHz. While RK3328 support higher rates
>> and it
>> +        * works in Linux, it doesn't seem to work in u-boot. That limits
>> max
>> +        * resolution to 1440p
>> +        */
>> +       return timing->pixelclock.typ <= 297000000;
>> +}
>> +
>>  static const struct dm_display_ops rk3328_hdmi_ops = {
>>         .read_edid = rk_hdmi_read_edid,
>>         .enable = rk3328_hdmi_enable,
>> +       .mode_valid = rk3328_hdmi_mode_valid,
>>  };
>>
>>  static const struct udevice_id rk3328_hdmi_ids[] = {
>> --
>> 2.49.0
>>
>>