On Wed, 18 Jan 2023, Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> wrote:
> On Wed, Jan 04, 2023 at 12:05:25PM +0200, Jani Nikula wrote:
>> Add a helper for skipping the HDMI VSDB audio latency fields.
>>
>> There's a functional change for HDMI VSDB blocks that do not respect the
>> spec: "I_Latency_Fields_Present shall be zero if Latency_Fields_Present
>> is zero". We assume this to hold when skipping the latency fields, and
>> ignore non-zero I_Latency_Fields_Present if Latency_Fields_Present is
>> zero.
>>
>> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
>
> Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Thanks for the reviews so far, pushed up to and including this patch to
drm-misc-next.
BR,
Jani.
>
>> ---
>> drivers/gpu/drm/drm_edid.c | 18 +++++++++++-------
>> 1 file changed, 11 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
>> index 847076b29594..93067b8dd9f6 100644
>> --- a/drivers/gpu/drm/drm_edid.c
>> +++ b/drivers/gpu/drm/drm_edid.c
>> @@ -4695,6 +4695,16 @@ static bool hdmi_vsdb_i_latency_present(const u8 *db)
>> return hdmi_vsdb_latency_present(db) && db[8] & BIT(6);
>> }
>>
>> +static int hdmi_vsdb_latency_length(const u8 *db)
>> +{
>> + if (hdmi_vsdb_i_latency_present(db))
>> + return 4;
>> + else if (hdmi_vsdb_latency_present(db))
>> + return 2;
>> + else
>> + return 0;
>> +}
>> +
>> /*
>> * do_hdmi_vsdb_modes - Parse the HDMI Vendor Specific data block
>> * @connector: connector corresponding to the HDMI sink
>> @@ -4720,13 +4730,7 @@ do_hdmi_vsdb_modes(struct drm_connector *connector, const u8 *db, u8 len)
>> if (!(db[8] & (1 << 5)))
>> goto out;
>>
>> - /* Latency_Fields_Present */
>> - if (db[8] & (1 << 7))
>> - offset += 2;
>> -
>> - /* I_Latency_Fields_Present */
>> - if (db[8] & (1 << 6))
>> - offset += 2;
>> + offset += hdmi_vsdb_latency_length(db);
>>
>> /* the declared length is not long enough for the 2 first bytes
>> * of additional video format capabilities */
>> --
>> 2.34.1
--
Jani Nikula, Intel Open Source Graphics Center
