Re: [PATCH] drm/dp: move intel_dp_vsc_sdp_pack() to generic helper

From: Ville Syrjälä
Date: Wed Feb 14 2024 - 13:09:12 EST

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In reply to: Abhinav Kumar: "Re: [PATCH] drm/dp: move intel_dp_vsc_sdp_pack() to generic helper"
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On Wed, Feb 14, 2024 at 09:17:34AM -0800, Abhinav Kumar wrote:
>
>
> On 2/14/2024 12:15 AM, Dmitry Baryshkov wrote:
> > On Wed, 14 Feb 2024 at 01:45, Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> wrote:
> >>
> >> intel_dp_vsc_sdp_pack() can be re-used by other DRM drivers as well.
> >> Lets move this to drm_dp_helper to achieve this.
> >>
> >> Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
> >
> > My preference would be to have packing functions in
> > drivers/video/hdmi.c, as we already have
> > hdmi_audio_infoframe_pack_for_dp() there.
> >
>
> My preference is drm_dp_helper because it already has some VSC SDP stuff
> and after discussion with Ville on IRC, I decided to post it this way.
>
> hdmi_audio_infoframe_pack_for_dp() is an exception from my PoV as the
> hdmi audio infoframe fields were re-used and packed into a DP SDP
> thereby re-using the existing struct hdmi_audio_infoframe .
>
> This is not like that. Here we pack from struct drm_dp_vsc_sdp to struct
> dp_sdp both of which had prior usages already in this file.
>
> So it all adds up and makes sense to me to be in this file.
>
> I will let the other DRM core maintainers comment on this.
>
> Ville, Jani?

Yeah, I'm not sure bloating the (poorly named) hdmi.c with all
SDP stuff is a great idea. Since other related stuff already
lives in the drm_dp_helper.c that seems reasonable to me at this
time. And if we get a decent amount of this then probably all
DP SDP stuff should be extracted into its own file.

There are of course a few overlaps here andthere (the audio SDP
I guess, and the CTA infoframe SDP). But I'm not sure that actually
needs any SDP specific stuff in hdmi.c, or could we just let hdmi.c
deal with the actual CTA-861 stuff and then have the DP SDP code
wrap that up in its own thing externally? Dunno, haven't really
looked at the details.

>
> >> ---
> >> drivers/gpu/drm/display/drm_dp_helper.c | 78 +++++++++++++++++++++++++
> >> drivers/gpu/drm/i915/display/intel_dp.c | 73 +----------------------
> >> include/drm/display/drm_dp_helper.h | 3 +
> >> 3 files changed, 84 insertions(+), 70 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
> >> index b1ca3a1100da..066cfbbf7a91 100644
> >> --- a/drivers/gpu/drm/display/drm_dp_helper.c
> >> +++ b/drivers/gpu/drm/display/drm_dp_helper.c
> >> @@ -2916,6 +2916,84 @@ void drm_dp_vsc_sdp_log(const char *level, struct device *dev,
> >> }
> >> EXPORT_SYMBOL(drm_dp_vsc_sdp_log);
> >>
> >> +/**
> >> + * drm_dp_vsc_sdp_pack() - pack a given vsc sdp into generic dp_sdp
> >> + * @vsc: vsc sdp initialized according to its purpose as defined in
> >> + * table 2-118 - table 2-120 in DP 1.4a specification
> >> + * @sdp: valid handle to the generic dp_sdp which will be packed
> >> + * @size: valid size of the passed sdp handle
> >> + *
> >> + * Returns length of sdp on success and error code on failure
> >> + */
> >> +ssize_t drm_dp_vsc_sdp_pack(const struct drm_dp_vsc_sdp *vsc,
> >> + struct dp_sdp *sdp, size_t size)
> >
> > I know that you are just moving the function. Maybe there can be
> > patch#2, which drops the size argument? The struct dp_sdp already has
> > a defined size. The i915 driver just passes sizeof(sdp), which is more
> > or less useless.
> >
>
> Yes this is a valid point, I also noticed this. I can post it on top of
> this once we get an agreement and ack on this patch first.
>
> >> +{
> >> + size_t length = sizeof(struct dp_sdp);
> >> +
> >> + if (size < length)
> >> + return -ENOSPC;
> >> +
> >> + memset(sdp, 0, size);
> >> +
> >> + /*
> >> + * Prepare VSC Header for SU as per DP 1.4a spec, Table 2-119
> >> + * VSC SDP Header Bytes
> >> + */
> >> + sdp->sdp_header.HB0 = 0; /* Secondary-Data Packet ID = 0 */
> >> + sdp->sdp_header.HB1 = vsc->sdp_type; /* Secondary-data Packet Type */
> >> + sdp->sdp_header.HB2 = vsc->revision; /* Revision Number */
> >> + sdp->sdp_header.HB3 = vsc->length; /* Number of Valid Data Bytes */
> >> +
> >> + if (vsc->revision == 0x6) {
> >> + sdp->db[0] = 1;
> >> + sdp->db[3] = 1;
> >> + }
> >> +
> >> + /*
> >> + * Revision 0x5 and revision 0x7 supports Pixel Encoding/Colorimetry
> >> + * Format as per DP 1.4a spec and DP 2.0 respectively.
> >> + */
> >> + if (!(vsc->revision == 0x5 || vsc->revision == 0x7))
> >> + goto out;
> >> +
> >> + /* VSC SDP Payload for DB16 through DB18 */
> >> + /* Pixel Encoding and Colorimetry Formats */
> >> + sdp->db[16] = (vsc->pixelformat & 0xf) << 4; /* DB16[7:4] */
> >> + sdp->db[16] |= vsc->colorimetry & 0xf; /* DB16[3:0] */
> >> +
> >> + switch (vsc->bpc) {
> >> + case 6:
> >> + /* 6bpc: 0x0 */
> >> + break;
> >> + case 8:
> >> + sdp->db[17] = 0x1; /* DB17[3:0] */
> >> + break;
> >> + case 10:
> >> + sdp->db[17] = 0x2;
> >> + break;
> >> + case 12:
> >> + sdp->db[17] = 0x3;
> >> + break;
> >> + case 16:
> >> + sdp->db[17] = 0x4;
> >> + break;
> >> + default:
> >> + WARN(1, "Missing case %d\n", vsc->bpc);
> >> + return -EINVAL;
> >> + }
> >> +
> >> + /* Dynamic Range and Component Bit Depth */
> >> + if (vsc->dynamic_range == DP_DYNAMIC_RANGE_CTA)
> >> + sdp->db[17] |= 0x80; /* DB17[7] */
> >> +
> >> + /* Content Type */
> >> + sdp->db[18] = vsc->content_type & 0x7;
> >> +
> >> +out:
> >> + return length;
> >> +}
> >> +EXPORT_SYMBOL(drm_dp_vsc_sdp_pack);
> >> +
> >> /**
> >> * drm_dp_get_pcon_max_frl_bw() - maximum frl supported by PCON
> >> * @dpcd: DisplayPort configuration data
> >> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> >> index f5ef95da5534..e94db51aeeb7 100644
> >> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> >> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> >> @@ -4110,73 +4110,6 @@ intel_dp_needs_vsc_sdp(const struct intel_crtc_state *crtc_state,
> >> return false;
> >> }
> >>
> >> -static ssize_t intel_dp_vsc_sdp_pack(const struct drm_dp_vsc_sdp *vsc,
> >> - struct dp_sdp *sdp, size_t size)
> >> -{
> >> - size_t length = sizeof(struct dp_sdp);
> >> -
> >> - if (size < length)
> >> - return -ENOSPC;
> >> -
> >> - memset(sdp, 0, size);
> >> -
> >> - /*
> >> - * Prepare VSC Header for SU as per DP 1.4a spec, Table 2-119
> >> - * VSC SDP Header Bytes
> >> - */
> >> - sdp->sdp_header.HB0 = 0; /* Secondary-Data Packet ID = 0 */
> >> - sdp->sdp_header.HB1 = vsc->sdp_type; /* Secondary-data Packet Type */
> >> - sdp->sdp_header.HB2 = vsc->revision; /* Revision Number */
> >> - sdp->sdp_header.HB3 = vsc->length; /* Number of Valid Data Bytes */
> >> -
> >> - if (vsc->revision == 0x6) {
> >> - sdp->db[0] = 1;
> >> - sdp->db[3] = 1;
> >> - }
> >> -
> >> - /*
> >> - * Revision 0x5 and revision 0x7 supports Pixel Encoding/Colorimetry
> >> - * Format as per DP 1.4a spec and DP 2.0 respectively.
> >> - */
> >> - if (!(vsc->revision == 0x5 || vsc->revision == 0x7))
> >> - goto out;
> >> -
> >> - /* VSC SDP Payload for DB16 through DB18 */
> >> - /* Pixel Encoding and Colorimetry Formats */
> >> - sdp->db[16] = (vsc->pixelformat & 0xf) << 4; /* DB16[7:4] */
> >> - sdp->db[16] |= vsc->colorimetry & 0xf; /* DB16[3:0] */
> >> -
> >> - switch (vsc->bpc) {
> >> - case 6:
> >> - /* 6bpc: 0x0 */
> >> - break;
> >> - case 8:
> >> - sdp->db[17] = 0x1; /* DB17[3:0] */
> >> - break;
> >> - case 10:
> >> - sdp->db[17] = 0x2;
> >> - break;
> >> - case 12:
> >> - sdp->db[17] = 0x3;
> >> - break;
> >> - case 16:
> >> - sdp->db[17] = 0x4;
> >> - break;
> >> - default:
> >> - MISSING_CASE(vsc->bpc);
> >> - break;
> >> - }
> >> - /* Dynamic Range and Component Bit Depth */
> >> - if (vsc->dynamic_range == DP_DYNAMIC_RANGE_CTA)
> >> - sdp->db[17] |= 0x80; /* DB17[7] */
> >> -
> >> - /* Content Type */
> >> - sdp->db[18] = vsc->content_type & 0x7;
> >> -
> >> -out:
> >> - return length;
> >> -}
> >> -
> >> static ssize_t
> >> intel_dp_hdr_metadata_infoframe_sdp_pack(struct drm_i915_private *i915,
> >> const struct hdmi_drm_infoframe *drm_infoframe,
> >> @@ -4269,8 +4202,8 @@ static void intel_write_dp_sdp(struct intel_encoder *encoder,
> >>
> >> switch (type) {
> >> case DP_SDP_VSC:
> >> - len = intel_dp_vsc_sdp_pack(&crtc_state->infoframes.vsc, &sdp,
> >> - sizeof(sdp));
> >> + len = drm_dp_vsc_sdp_pack(&crtc_state->infoframes.vsc, &sdp,
> >> + sizeof(sdp));
> >> break;
> >> case HDMI_PACKET_TYPE_GAMUT_METADATA:
> >> len = intel_dp_hdr_metadata_infoframe_sdp_pack(dev_priv,
> >> @@ -4297,7 +4230,7 @@ void intel_write_dp_vsc_sdp(struct intel_encoder *encoder,
> >> struct dp_sdp sdp = {};
> >> ssize_t len;
> >>
> >> - len = intel_dp_vsc_sdp_pack(vsc, &sdp, sizeof(sdp));
> >> + len = drm_dp_vsc_sdp_pack(vsc, &sdp, sizeof(sdp));
> >>
> >> if (drm_WARN_ON(&dev_priv->drm, len < 0))
> >> return;
> >> diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h
> >> index 863b2e7add29..f8db34a2f7a5 100644
> >> --- a/include/drm/display/drm_dp_helper.h
> >> +++ b/include/drm/display/drm_dp_helper.h
> >> @@ -813,4 +813,7 @@ int drm_dp_bw_overhead(int lane_count, int hactive,
> >> int bpp_x16, unsigned long flags);
> >> int drm_dp_bw_channel_coding_efficiency(bool is_uhbr);
> >>
> >> +ssize_t drm_dp_vsc_sdp_pack(const struct drm_dp_vsc_sdp *vsc,
> >> + struct dp_sdp *sdp, size_t size);
> >> +
> >> #endif /* _DRM_DP_HELPER_H_ */
> >> --
> >> 2.34.1
> >>
> >
> >

--
Ville Syrjälä
Intel

Next message: Bjorn Andersson: "Re: [PATCH v3] ARM: dts: qcom: msm8974: correct qfprom node size"
Previous message: Andrew Lunn: "Re: [PATCH net-next] net: phy: qca807x: move interface mode check to .config_init_once"
In reply to: Abhinav Kumar: "Re: [PATCH] drm/dp: move intel_dp_vsc_sdp_pack() to generic helper"
Next in thread: Abhinav Kumar: "Re: [PATCH] drm/dp: move intel_dp_vsc_sdp_pack() to generic helper"
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