[PATCH] drm/drm_edid: correct VIC and HDMI_VIC under HDMI 2.0
Lin, Wayne
Wayne.Lin at amd.com
Fri Oct 4 10:41:20 UTC 2019
________________________________
From: Ville Syrjälä <ville.syrjala at linux.intel.com>
Sent: Thursday, October 3, 2019 21:29
To: Lin, Wayne <Wayne.Lin at amd.com>
Cc: dri-devel at lists.freedesktop.org <dri-devel at lists.freedesktop.org>; amd-gfx at lists.freedesktop.org <amd-gfx at lists.freedesktop.org>; Li, Sun peng (Leo) <Sunpeng.Li at amd.com>; Kazlauskas, Nicholas <Nicholas.Kazlauskas at amd.com>
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 at linux.intel.com>
> Sent: Wednesday, October 2, 2019 19:58
> To: Lin, Wayne <Wayne.Lin at amd.com>
> Cc: dri-devel at lists.freedesktop.org <dri-devel at lists.freedesktop.org>; amd-gfx at lists.freedesktop.org <amd-gfx at lists.freedesktop.org>; Li, Sun peng (Leo) <Sunpeng.Li at amd.com>; Kazlauskas, Nicholas <Nicholas.Kazlauskas at amd.com>
> 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 .
>
> > The same situation occurs in drm_hdmi_vendor_infoframe_from_display_mode
> > and should set HDMI_VIC when the mode is one defined in HDMI 1.4b 4K
> > modes.
>
> > Yes, and we do that. "vic = drm_match_hdmi_mode(mode);"
>
> > Apart from adding the aspect ratios I don't really understand what
> > you're trying to achieve here.
>
> For HDMI 2.0 sink, drm_match_hdmi_mode() should also take aspect ratio into consideration.
> Once again, very appreciate for your time.
>
> > ---
> > drivers/gpu/drm/drm_edid.c | 95 ++++++++++++++++++++++++++++++++++++--
> > 1 file changed, 92 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> > index 649cfd8b4200..0fea9bf4ec67 100644
> > --- a/drivers/gpu/drm/drm_edid.c
> > +++ b/drivers/gpu/drm/drm_edid.c
> > @@ -1306,6 +1306,37 @@ static const struct drm_display_mode edid_4k_modes[] = {
> > .vrefresh = 24, },
> > };
> >
> > +/*
> > + * 4k modes of HDMI 1.4 defined in HDMI 2.0. Index using the VIC.
> > + */
> > +static const struct drm_display_mode hdmi_1_4_edid_4k_modes[] = {
> > + /* 0 - dummy, VICs start at 1 */
> > + { },
> > + /* 1 - 3840x2160 at 30Hz */
> > + { DRM_MODE("3840x2160", DRM_MODE_TYPE_DRIVER, 297000,
> > + 3840, 4016, 4104, 4400, 0,
> > + 2160, 2168, 2178, 2250, 0,
> > + DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC),
> > + .vrefresh = 30, .picture_aspect_ratio = HDMI_PICTURE_ASPECT_16_9, },
> > + /* 2 - 3840x2160 at 25Hz */
> > + { DRM_MODE("3840x2160", DRM_MODE_TYPE_DRIVER, 297000,
> > + 3840, 4896, 4984, 5280, 0,
> > + 2160, 2168, 2178, 2250, 0,
> > + DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC),
> > + .vrefresh = 25, .picture_aspect_ratio = HDMI_PICTURE_ASPECT_16_9, },
> > + /* 3 - 3840x2160 at 24Hz */
> > + { DRM_MODE("3840x2160", DRM_MODE_TYPE_DRIVER, 297000,
> > + 3840, 5116, 5204, 5500, 0,
> > + 2160, 2168, 2178, 2250, 0,
> > + DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC),
> > + .vrefresh = 24, .picture_aspect_ratio = HDMI_PICTURE_ASPECT_16_9, },
> > + /* 4 - 4096x2160 at 24Hz (SMPTE) */
> > + { DRM_MODE("4096x2160", DRM_MODE_TYPE_DRIVER, 297000,
> > + 4096, 5116, 5204, 5500, 0,
> > + 2160, 2168, 2178, 2250, 0,
> > + DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC),
> > + .vrefresh = 24, .picture_aspect_ratio = HDMI_PICTURE_ASPECT_256_135, },
> > +};
> > /*** DDC fetch and block validation ***/
> >
> > static const u8 edid_header[] = {
> > @@ -3061,6 +3092,19 @@ hdmi_mode_alternate_clock(const struct drm_display_mode *hdmi_mode)
> > return cea_mode_alternate_clock(hdmi_mode);
> > }
> >
> > +/*
> > + * Calculate the alternate clock for HDMI modes (those from the HDMI vendor
> > + * specific block).
> > + *
> > + * It's almost like hdmi_mode_alternate_clock(), but no exception for VIC 4 mode.
> > + * There is an alternate clock (23.98Hz) of VIC 4 mode (4096x2160 at 24Hz) in HDMI 2.0
> > + */
> > +static unsigned int
> > +hdmi_1_4_mode_alternate_clock(const struct drm_display_mode *hdmi_mode)
> > +{
> > + return cea_mode_alternate_clock(hdmi_mode);
> > +}
> > +
> > static u8 drm_match_hdmi_mode_clock_tolerance(const struct drm_display_mode *to_match,
> > unsigned int clock_tolerance)
> > {
> > @@ -3121,11 +3165,53 @@ static u8 drm_match_hdmi_mode(const struct drm_display_mode *to_match)
> > return 0;
> > }
> >
> > +/*
> > + * drm_match_hdmi_1_4_mode - look for a HDMI 1.4 mode matching given mode
> > + * @to_match: display mode
> > + *
> > + * An HDMI mode is one defined in the HDMI vendor specific block.
> > + * In HDMI 2.0, only few 4k resolutions with specific aspect ratio should
> > + * utilize H14b VSIF.
> > + *
> > + * Returns the HDMI Video ID (VIC) of the mode or 0 if it isn't one.
> > + */
> > +static u8 drm_match_hdmi_1_4_mode(const struct drm_display_mode *to_match)
> > +{
> > + unsigned int match_flags = DRM_MODE_MATCH_TIMINGS | DRM_MODE_MATCH_FLAGS;
> > + u8 vic;
> > +
> > + if (!to_match->clock)
> > + return 0;
> > +
> > + if (to_match->picture_aspect_ratio)
> > + match_flags |= DRM_MODE_MATCH_ASPECT_RATIO;
> > +
> > + for (vic = 1; vic < ARRAY_SIZE(hdmi_1_4_edid_4k_modes); vic++) {
> > + const struct drm_display_mode *hdmi_1_4_mode = &hdmi_1_4_edid_4k_modes[vic];
> > + unsigned int clock1, clock2;
> > +
> > + /* Make sure to also match alternate clocks */
> > + clock1 = hdmi_1_4_mode->clock;
> > + clock2 = hdmi_1_4_mode_alternate_clock(hdmi_1_4_mode);
> > +
> > + if ((KHZ2PICOS(to_match->clock) == KHZ2PICOS(clock1) ||
> > + KHZ2PICOS(to_match->clock) == KHZ2PICOS(clock2)) &&
> > + drm_mode_match(to_match, hdmi_1_4_mode, match_flags))
> > + return vic;
> > + }
> > + return 0;
> > +}
> > +
> > static bool drm_valid_hdmi_vic(u8 vic)
> > {
> > return vic > 0 && vic < ARRAY_SIZE(edid_4k_modes);
> > }
> >
> > +static bool drm_valid_hdmi_1_4_vic(u8 vic)
> > +{
> > + return vic > 0 && vic < ARRAY_SIZE(hdmi_1_4_edid_4k_modes);
> > +}
> > +
> > static int
> > add_alternate_cea_modes(struct drm_connector *connector, struct edid *edid)
> > {
> > @@ -4894,10 +4980,12 @@ drm_hdmi_avi_infoframe_from_display_mode(struct hdmi_avi_infoframe *frame,
> > * HDMI 1.4b 4K modes
> > */
> > if (frame->video_code) {
> > - u8 vendor_if_vic = drm_match_hdmi_mode(mode);
> > + u8 vendor_if_vic = is_hdmi2_sink(connector) ?
> > + drm_match_hdmi_1_4_mode(mode) : drm_match_hdmi_mode(mode);
> > bool is_s3d = mode->flags & DRM_MODE_FLAG_3D_MASK;
> >
> > - if (drm_valid_hdmi_vic(vendor_if_vic) && !is_s3d)
> > + if (!is_s3d && is_hdmi2_sink(connector) ?
> > + drm_valid_hdmi_1_4_vic(vendor_if_vic) : drm_valid_hdmi_vic(vendor_if_vic))
> > frame->video_code = 0;
> > }
> >
> > @@ -5125,7 +5213,8 @@ drm_hdmi_vendor_infoframe_from_display_mode(struct hdmi_vendor_infoframe *frame,
> > if (!has_hdmi_infoframe)
> > return -EINVAL;
> >
> > - vic = drm_match_hdmi_mode(mode);
> > + vic = is_hdmi2_sink(connector) ?
> > + drm_match_hdmi_1_4_mode(mode) : drm_match_hdmi_mode(mode);
> > s3d_flags = mode->flags & DRM_MODE_FLAG_3D_MASK;
> >
> > /*
> > --
> > 2.17.1
> >
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
> --
> Ville Syrjälä
> Intel
> --
> Ville Syrjälä
> Intel
--
Best regards,
Wayne Lin
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