Hi Jani,
> -----Original Message-----
> From: Jani Nikula <[email protected]>
> Sent: Monday, September 7, 2026 3:40 PM
> To: Samala, Pranay <[email protected]>; intel-
> [email protected]; [email protected]
> Cc: Borah, Chaitanya Kumar <[email protected]>;
> Lattannavar, Sameer <[email protected]>; Samala, Pranay
> <[email protected]>
> Subject: Re: [PATCH] drm/i915/debugfs: Add HDR status to i915_display_info
>
> On Mon, 07 Sep 2026, Pranay Samala <[email protected]> wrote:
> > i915_display_info currently shows per-connector state but not HDR
> > status, making HDR bringup hard to debug without correlating EDID,
> > userspace, and driver state.
> >
> > Print the sink’s HDR capability from the EDID static metadata block,
> > whether userspace has set the HDR_OUTPUT_METADATA property, and
> > whether the driver is actually transmitting HDR metadata in the CRTC
> > state. This distinguishes between a sink advertising HDR support, a
> > property being set by userspace, and the actual HDR infoframe being sent
> on the wire.
> >
> > Assisted-by: GitHub_Copilot:claude-opus-5
> > Signed-off-by: Pranay Samala <[email protected]>
> > ---
> > .../drm/i915/display/intel_display_debugfs.c | 82
> > +++++++++++++++++++
> > 1 file changed, 82 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > index 3e302f23f247..a24c947c23de 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > @@ -243,6 +243,86 @@ static void intel_hdmi_info(struct seq_file *m,
> > seq_printf(m, "\taudio support: %s\n", str_yes_no(has_audio)); }
> >
> > +static const char *intel_hdr_eotf_name(enum hdmi_eotf eotf) {
> > + switch (eotf) {
> > + case HDMI_EOTF_TRADITIONAL_GAMMA_SDR:
> > + return "SDR";
> > + case HDMI_EOTF_TRADITIONAL_GAMMA_HDR:
> > + return "HDR-gamma";
> > + case HDMI_EOTF_SMPTE_ST2084:
> > + return "SMPTE_ST2084";
> > + case HDMI_EOTF_BT_2100_HLG:
> > + return "HLG";
> > + default:
> > + return "unknown";
> > + }
> > +}
>
> Maybe add that to hdmi.[ch] instead of a local copy? There's nothing Intel or
> i915 specific about this.
>
Agreed. enum hdmi_eotf already lives in include/linux/hdmi.h.
For v2 I'll add hdmi_eotf_get_name() to drivers/video/hdmi.c alongside
the existing hdmi_*_get_name() helpers.
intel_hdr_eotf_name() then goes away entirely.
> > +
> > +static void intel_hdr_sink_info(struct seq_file *m,
> > + struct drm_connector *connector)
> > +{
>
> If you did
>
> struct drm_printer p = drm_seq_file_printer(m);
>
> in the caller, and passed struct drm_printer *p here, you could use
> drm_printf_indent() and avoid doing that \t stuff everywhere.
>
Sure, Will do.
> Side note, I've got a branch converting the entire file to drm_printer, but
> never got around to sending it.
>
Happy to rebase on that if you'd rather send it first, so we're not both
touching the same lines. Otherwise, I'll post v2 using drm_printer as
above, it should rebase cleanly onto your conversion either way.
Thanks for the review.
Regards,
Pranay
>
> BR,
> Jani.
>
>
> > + const struct hdr_static_metadata *hdr =
> > + &connector->display_info.hdr_sink_metadata.hdmi_type1;
> > + int i;
> > +
> > + seq_printf(m, "\tHDR sink capable: %s\n",
> > + str_yes_no(hdr->eotf & (BIT(HDMI_EOTF_SMPTE_ST2084) |
> > + BIT(HDMI_EOTF_BT_2100_HLG))));
> > + if (!hdr->eotf)
> > + return;
> > +
> > + seq_puts(m, "\t\tsupported EOTF:");
> > + for (i = HDMI_EOTF_TRADITIONAL_GAMMA_SDR; i <=
> HDMI_EOTF_BT_2100_HLG; i++)
> > + if (hdr->eotf & BIT(i))
> > + seq_printf(m, " %s", intel_hdr_eotf_name(i));
> > + seq_puts(m, "\n");
> > +
> > + seq_printf(m, "\t\tstatic metadata type1: %s\n",
> > + str_yes_no(hdr->metadata_type &
> BIT(HDMI_STATIC_METADATA_TYPE1)));
> > + seq_printf(m, "\t\tmax_cll: %u, max_fall: %u, min_cll: %u (EDID
> coded)\n",
> > + hdr->max_cll, hdr->max_fall, hdr->min_cll); }
> > +
> > +static void intel_hdr_output_info(struct seq_file *m,
> > + struct drm_connector *connector) {
> > + const struct drm_connector_state *conn_state = connector->state;
> > + const struct intel_crtc_state *crtc_state;
> > + const struct hdmi_drm_infoframe *frame;
> > +
> > + if (!conn_state || !conn_state->crtc)
> > + return;
> > +
> > + crtc_state = to_intel_crtc_state(conn_state->crtc->state);
> > +
> > + seq_printf(m, "\tHDR output metadata blob: %s\n",
> > + str_yes_no(conn_state->hdr_output_metadata));
> > +
> > + /* HDMI signals HDR via a DRM InfoFrame, DP via a gamut metadata
> SDP */
> > + if (!(crtc_state->infoframes.enable &
> > + (intel_hdmi_infoframe_enable(HDMI_INFOFRAME_TYPE_DRM) |
> > +
> intel_hdmi_infoframe_enable(HDMI_PACKET_TYPE_GAMUT_METADATA)))) {
> > + seq_puts(m, "\tHDR output: off\n");
> > + return;
> > + }
> > +
> > + frame = &crtc_state->infoframes.drm.drm;
> > +
> > + seq_printf(m, "\tHDR output: on, EOTF: %s, metadata type: %d\n",
> > + intel_hdr_eotf_name(frame->eotf), frame-
> >metadata_type);
> > + seq_printf(m, "\t\tprimaries: r(%u,%u) g(%u,%u) b(%u,%u)
> wp(%u,%u)\n",
> > + frame->display_primaries[0].x, frame-
> >display_primaries[0].y,
> > + frame->display_primaries[1].x, frame-
> >display_primaries[1].y,
> > + frame->display_primaries[2].x, frame-
> >display_primaries[2].y,
> > + frame->white_point.x, frame->white_point.y);
> > + seq_printf(m, "\t\tmastering luminance: max %u, min %u\n",
> > + frame->max_display_mastering_luminance,
> > + frame->min_display_mastering_luminance);
> > + seq_printf(m, "\t\tmax_cll: %u, max_fall: %u\n",
> > + frame->max_cll, frame->max_fall); }
> > +
> > static void intel_connector_info(struct seq_file *m,
> > struct drm_connector *connector) { @@ -
> 264,6 +344,7 @@ static
> > void intel_connector_info(struct seq_file *m,
> > seq_printf(m, "\tsubpixel order: %s\n",
> > drm_get_subpixel_order_name(connector-
> >display_info.subpixel_order));
> > seq_printf(m, "\tCEA rev: %d\n", connector->display_info.cea_rev);
> > + intel_hdr_sink_info(m, connector);
> >
> > switch (connector->connector_type) {
> > case DRM_MODE_CONNECTOR_DisplayPort:
> > @@ -288,6 +369,7 @@ static void intel_connector_info(struct seq_file *m,
> > intel_hdcp_info(m, intel_connector);
> >
> > seq_printf(m, "\tmax bpc: %u\n", connector->display_info.bpc);
> > + intel_hdr_output_info(m, connector);
> >
> > intel_panel_info(m, intel_connector);
>
> --
> Jani Nikula, Intel
