Hi, On 13/11/2020 11:46, Yuti Amonkar wrote: > This patch series add bus format negotiation support for Cadence MHDP8546 > bridge > driver. > > The patch series has four patches in the below sequence: > 1. drm: bridge: cdns-mhdp8546: Add output bus format negotiation > Add minimal output bus format negotiation support. > 2. drm: bridge: cdns-mhdp8546: Modify atomic_get_input_bus_format bridge > function. > Get the input format based on output format supported. > 3. drm: bridge: cdns-mhdp8546: Remove setting of bus format using connector > info > Remove the bus format configuration using connector info structure. > 4. drm: bridge: cdns-mhdp8546: Retrieve the pixel format and bpc based on bus > format > Get the pixel format and bpc based on negotiated output bus format. > > This patch series is dependent on tidss series [1] for the new connector > model support. > > [1] > https://patchwork.kernel.org/project/dri-devel/cover/20201109170601.21557-1-nikhil...@ti.com/ >
Can you explain how this works? Afaics, what we should be doing is: - We don't have proper bus formats for DP output, so we need to use MEDIA_BUS_FMT_FIXED as the output format. This is what you do in the first patch. (But is that patch even needed, if MEDIA_BUS_FMT_FIXED is the default anyway) - In cdns_mhdp_get_input_bus_fmts, the function should exit if the given output format is not MEDIA_BUS_FMT_FIXED. - In cdns_mhdp_get_input_bus_fmts, the driver should return all the RGB bus formats, if MHDP is able to upscale/downscale RGB (e.g. RGB 8-bpc to RGB 12-bpc). - If the monitor supports YUV modes according to the display_info, cdns_mhdp_get_input_bus_fmts can also return those. - Then later, in atomic_check and commit, mhdp driver has the negotiated bus format, which it should use to program the registers. Tomi -- Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
