On 30/11/2020 11:46, Laurent Pinchart wrote: > Hi Nikhil, > > On Mon, Nov 30, 2020 at 12:05:03PM +0530, Nikhil Devshatwar wrote: >> On 14:51-20201125, Tomi Valkeinen wrote: >>> On 19/11/2020 18:01, Nikhil Devshatwar wrote: >>>> Remove the old code to iterate over the bridge chain, as this is >>>> already done by the framework. >>>> The bridge state should have the negotiated bus format and flags. >>>> Use these from the bridge's state. >>>> If the bridge does not support format negotiation, error out >>>> and fail. >>>> >>>> Signed-off-by: Nikhil Devshatwar <nikhil.nd@xxxxxx> >>>> Reviewed-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx> >>>> --- >>>> >>>> Notes: >>>> changes from v2: >>>> * Remove the old code and use the flags from the bridge state >>>> >>>> drivers/gpu/drm/tidss/tidss_encoder.c | 36 +++++++++++---------------- >>>> 1 file changed, 14 insertions(+), 22 deletions(-) >>> >>> If a first bridge (after the crtc) supports two bus formats as input, how does tidss choose between >>> those? This patch just picks bstate->input_bus_cfg.format, and it's not clear to me which one that >>> is (the first one?). Also, we don't check if tidss actually supports the bus format. >> >> The selection is done by the framework in >> select_bus_fmt_recursive at drivers/gpu/drm/drm_bridge.c:810 >> >> My understanding is that currently, the format negotiation logic does >> not negotiate all the way till encoder, it stops only at the >> first_bridge. > > Should we then implement a bridge in the tidss driver to model the > internal encoder, in order to support format negotiation all the way to > the tidss ? I don't know, but it feels perhaps a bit odd. Then we would have crtc + encoder + bridge, which are actually all about the same HW block. And this would have to be done for all DRM drivers. Tomi -- Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
