On Fri, Oct 04, 2019 at 10:41:20AM +0000, Lin, Wayne wrote: > > > ________________________________ > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > Sent: Thursday, October 3, 2019 21:29 > To: Lin, Wayne <Wayne.Lin@xxxxxxx> > Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx <dri-devel@xxxxxxxxxxxxxxxxxxxxx>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx <amd-gfx@xxxxxxxxxxxxxxxxxxxxx>; Li, Sun peng (Leo) <Sunpeng.Li@xxxxxxx>; Kazlauskas, Nicholas <Nicholas.Kazlauskas@xxxxxxx> > Subject: Re: [PATCH] drm/drm_edid: correct VIC and HDMI_VIC under HDMI 2.0 > > On Thu, Oct 03, 2019 at 06:49:05AM +0000, Lin, Wayne wrote: > > > > > > ________________________________ > > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > Sent: Wednesday, October 2, 2019 19:58 > > To: Lin, Wayne <Wayne.Lin@xxxxxxx> > > Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx <dri-devel@xxxxxxxxxxxxxxxxxxxxx>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx <amd-gfx@xxxxxxxxxxxxxxxxxxxxx>; Li, Sun peng (Leo) <Sunpeng.Li@xxxxxxx>; Kazlauskas, Nicholas <Nicholas.Kazlauskas@xxxxxxx> > > Subject: Re: [PATCH] drm/drm_edid: correct VIC and HDMI_VIC under HDMI 2.0 > > > > On Tue, Sep 24, 2019 at 01:26:21PM +0800, Wayne Lin wrote: > > > In HDMI 1.4 defines 4k modes without specific aspect ratio. > > > However, in HDMI 2.0, adds aspect ratio attribute to distinguish different > > > 4k modes. > > > > > > According to Appendix E of HDMI 2.0 spec, source should use VSIF to > > > indicate VIC mode only when the mode is one defined in HDMI 1.4b 4K modes. > > > Otherwise, use AVI infoframes to convey VIC. > > > > > > eg: VIC_103 should use AVI infoframes and VIC_93 use VSIF > > > > > > When the sink is HDMI 2.0, current code in > > > drm_hdmi_avi_infoframe_from_display_mode will also force mode VIC_103 to > > > have VIC value 0. This violates the spec and needs to be corrected. > > > > > Where is that being done? We only set the AVI VIC to zero if we're going > > > to use the HDMI VIC instead. > > > > Appreciate for your time and apologize for not explaining it clearly. > > Current code in drm_hdmi_avi_infoframe_from_display_mode() will call > > drm_match_hdmi_mode() to set up vendor_if_vic. By checking > > drm_valid_hdmi_vic(vendor_if_vic) to see if the vic info should be conveyed by avi > > or not. > > > > But in drm_match_hdmi_mode(), code doesn't enable match_flags with > > DRM_MODE_MATCH_ASPECT_RATIO. I think it's due to HDMI1.4b doesn't specify > > 4K mode conveyed by HDMI VIC with particular aspect ratio. But in Appendix E of > > HDMI 2.0 spec, it specify only 4k modes with particular aspect ratio should use VSIF to convey. > > Hence, when the sink support HDMI 2.0 and set the mode to be VIC_103, calling > > drm_match_hdmi_mode(mode) will return vendor_if_vic = 3 (VIC_93 and VIC_103 are having > > the same timing but different aspect ratio). Thereafter will set the frame->video_code to 0. > > However, VIC_103 should use AVI VIC according to HDMI 2.0 spec (only VIC: 93, 94, 95 & > > 98 should use VSIF). > > > > This patch try to revise that, when the sink support HDMI 2.0, drm_match_hdmi_mode() > > should also take aspect ratio into consideration. > > But for easy reading, I add another function "drm_match_hdmi_1_4_mode" to do so. > > > Seems rather convoluted. I think we should just add the aspect ratios > > to edid_4k_modes[]. Or is there some problem with that approach? > > Thanks for your time. > > Since HDMI 1.4b doesn't require edid_4k_modes[] with specific aspect ratio, modes as the same > timing in edid_4k_modes[] but with different aspect ratios are also expected to convey VIC by > VSIF to HDMI 1.4 sink. Might can't guarantee that there wont't be any compatibility side effect with > that approach when the sink is HDMI 1.4b . I think adding them should be fine. But while checking the existing code I noticed a few problems, so I sent out some fixes (cc:d you). -- Ville Syrjälä Intel _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx
