Re: [PATCH v9 46/61] drm/rockchip: rk3066_hdmi: Advertise HDMI 1.4 capabilities

[Cristian Ciocaltea]

Hi Diederik,

On 7/23/26 12:02 PM, Diederik de Haas wrote:
> Hi Cristian,
> 
> On Thu Jul 23, 2026 at 3:35 AM CEST, Cristian Ciocaltea wrote:
>> Bridges using DRM_BRIDGE_OP_HDMI are now expected to also provide a
>> supported HDMI version.  This is not yet enforced, but will become
>> mandatory once the migration to the new caps-based HDMI connector
>> initialization API is completed.
>>
>> The RK3066 HDMI TX supports HDMI 1.4a, as described in commit
>> f84d3d37b7fb ("drm: rockchip: introduce rk3066 hdmi").  However, the
>> driver does not currently enforce a maximum TMDS character rate, it only
>> filters non-CEA modes and excludes VIC 1 (640x480) via the .mode_valid
>> callback.
>>
>> Advertise HDMI 1.4 support for now so that modes exceeding the 340 MHz
>> TMDS limit are rejected by the core.
>>
>> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@xxxxxxxxxxxxx>
>> ---
>>  drivers/gpu/drm/rockchip/rk3066_hdmi.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/rockchip/rk3066_hdmi.c b/drivers/gpu/drm/rockchip/rk3066_hdmi.c
>> index f28d6a883e09..c080abe676c4 100644
>> --- a/drivers/gpu/drm/rockchip/rk3066_hdmi.c
>> +++ b/drivers/gpu/drm/rockchip/rk3066_hdmi.c
>> @@ -14,6 +14,7 @@
>>  #include <drm/drm_probe_helper.h>
>>  
>>  #include <linux/clk.h>
>> +#include <linux/hdmi.h>
>>  #include <linux/mfd/syscon.h>
>>  #include <linux/platform_device.h>
>>  #include <linux/regmap.h>
>> @@ -712,6 +713,7 @@ rk3066_hdmi_register(struct drm_device *drm, struct rk3066_hdmi *hdmi)
>>  	hdmi->bridge.type = DRM_MODE_CONNECTOR_HDMIA;
>>  	hdmi->bridge.vendor = "Rockchip";
>>  	hdmi->bridge.product = "RK3066 HDMI";
>> +	hdmi->bridge.supported_hdmi_ver = HDMI_VERSION_1_3;
> 
> Is this correct or should this be HDMI_VERSION_1_4 ?
> In the other 'Advertise HDMI N.M capabilities' patches, there is a (direct)
> match between the version mention in the commit summary and the
> supported_hdmi_ver property, but not here.

This is indeed a mismatch between the commit description and the actual code
changes.  It has no functional impact, as HDMI 1.3 and HDMI 1.4 are equivalent
in terms of the maximum supported TMDS character rate, which is what we
currently infer.

I'll set it to HDMI_VERSION_1_4 in the next revision.

Thanks,
Cristian