Hi Uma Shankar,
Thanks for the comments and suggestions.
Please find my response inline.
On 12/13/2020 12:40 PM, Shankar, Uma wrote:
-----Original Message-----
From: Nautiyal, Ankit K <ankit.k.nauti...@intel.com>
Sent: Tuesday, December 8, 2020 1:22 PM
To: intel-...@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org; Shankar, Uma <uma.shan...@intel.com>;
airl...@linux.ie; jani.nik...@linux.intel.com; ville.syrj...@linux.intel.com;
Kulkarni, Vandita <vandita.kulka...@intel.com>; Sharma, Swati2
<swati2.sha...@intel.com>
Subject: [PATCH v4 07/16] drm/dp_helper: Add helpers to configure PCONs RGB-
YCbCr Conversion
DP Specification for DP2.0 to HDMI2.1 Pcon specifies support for conversion of
colorspace from RGB to YCbCr.
https://groups.vesa.org/wg/DP/document/previewpdf/15651
This patch adds the relavant registers and helper functions to get the
capability
and set the color conversion bits for rgb->ycbcr conversion through PCON.
Signed-off-by: Ankit Nautiyal <ankit.k.nauti...@intel.com>
---
drivers/gpu/drm/drm_dp_helper.c | 59 +++++++++++++++++++++++++++++++++
include/drm/drm_dp_helper.h | 10 +++++-
2 files changed, 68 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_dp_helper.c
b/drivers/gpu/drm/drm_dp_helper.c index d0626f57f99c..344662d5c295 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -949,6 +949,35 @@ bool
drm_dp_downstream_444_to_420_conversion(const u8
dpcd[DP_RECEIVER_CAP_SIZE] }
EXPORT_SYMBOL(drm_dp_downstream_444_to_420_conversion);
+/**
+ * drm_dp_downstream_rgb_to_ycbcr_conversion() - determine downstream
facing port
+ * RGB->YCbCr conversion
capability
+ * @dpcd: DisplayPort configuration data
+ * @port_cap: downstream facing port capabilities
+ *
+ * Returns: whether the downstream facing port can convert RGB->YCbCr
+*/ bool drm_dp_downstream_rgb_to_ycbcr_conversion(const u8
+dpcd[DP_RECEIVER_CAP_SIZE],
+ const u8 port_cap[4])
+{
+ if (!drm_dp_is_branch(dpcd))
+ return false;
+
+ if (dpcd[DP_DPCD_REV] < 0x13)
+ return false;
+
+ switch (port_cap[0] & DP_DS_PORT_TYPE_MASK) {
+ case DP_DS_PORT_TYPE_HDMI:
+ if ((dpcd[DP_DOWNSTREAMPORT_PRESENT] &
DP_DETAILED_CAP_INFO_AVAILABLE) == 0)
+ return false;
+
+ return port_cap[3] & DP_DS_HDMI_BT601_RGB_YCBCR_CONV;
I guess there are other conversions also possible, like BT709 and 2020. Update
those
as well here.
Yes you are right. I will modify the function to take as input
colorspace, also and
the function will be returning true, if the rgb->ycbcr conversion for
the given colorspace is supported.
+ default:
+ return false;
+ }
+}
+EXPORT_SYMBOL(drm_dp_downstream_rgb_to_ycbcr_conversion);
+
/**
* drm_dp_downstream_mode() - return a mode for downstream facing port
* @dev: DRM device
@@ -3140,3 +3169,33 @@ int drm_dp_pcon_pps_override_param(struct
drm_dp_aux *aux, u8 pps_param[6])
return 0;
}
EXPORT_SYMBOL(drm_dp_pcon_pps_override_param);
+
+/*
+ * drm_dp_pcon_convert_rgb_to_ycbcr() - Configure the PCon to convert
+RGB to Ycbcr
+ * @aux: displayPort AUX channel
+ * @color_spc: Color space conversion type
+ *
+ * Returns 0 on success, else returns negative error code.
+ */
+int drm_dp_pcon_convert_rgb_to_ycbcr(struct drm_dp_aux *aux, u8
+color_spc) {
+ int ret;
+ u8 buf;
+
+ if (color_spc != DP_CONVERSION_BT601_RGB_YCBCR_ENABLE ||
+ color_spc != DP_CONVERSION_BT709_RGB_YCBCR_ENABLE ||
+ color_spc != DP_CONVERSION_BT2020_RGB_YCBCR_ENABLE)
+ return -EINVAL;
Yeah this is wrong, fix it.
Agreed. Will fix this in next version of the patch.
+
+ ret = drm_dp_dpcd_readb(aux, DP_PROTOCOL_CONVERTER_CONTROL_2,
&buf);
+ if (ret < 0)
+ return ret;
+
+ buf |= color_spc;
+ ret = drm_dp_dpcd_writeb(aux,
DP_PROTOCOL_CONVERTER_CONTROL_2, buf);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_dp_pcon_convert_rgb_to_ycbcr);
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index
347b4e1a55b4..1b3d54ed7a78 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -431,6 +431,9 @@ struct drm_device;
# define DP_DS_HDMI_YCBCR420_PASS_THROUGH (1 << 2)
# define DP_DS_HDMI_YCBCR444_TO_422_CONV (1 << 3)
# define DP_DS_HDMI_YCBCR444_TO_420_CONV (1 << 4)
+# define DP_DS_HDMI_BT601_RGB_YCBCR_CONV (1 << 5)
+# define DP_DS_HDMI_BT709_RGB_YCBCR_CONV (1 << 6)
+# define DP_DS_HDMI_BT2020_RGB_YCBCR_CONV (1 << 7)
I think it would be good to mention the location in spec (section or table),
will make it easier to understand/review by directly going to relevant sections
in spec.
This is still Draft 1 of the spec: VESA DP-to-HDMI PCON Specification
Standalone Document. Link in the commit message.
I will mention the current Section and Table no. nevertheless in the
next version of the patch.
Thanks & Regards,
Ankit
#define DP_MAX_DOWNSTREAM_PORTS 0x10
@@ -1217,7 +1220,9 @@ struct drm_device;
# define DP_PCON_ENC_PPS_OVERRIDE_DISABLED 0
# define DP_PCON_ENC_PPS_OVERRIDE_EN_PARAMS 1
# define DP_PCON_ENC_PPS_OVERRIDE_EN_BUFFER 2
-
+# define DP_CONVERSION_BT601_RGB_YCBCR_ENABLE (1 << 4) # define
+DP_CONVERSION_BT709_RGB_YCBCR_ENABLE (1 << 5) # define
+DP_CONVERSION_BT2020_RGB_YCBCR_ENABLE (1 << 6)
/* PCON Downstream HDMI ERROR Status per Lane */
#define DP_PCON_HDMI_ERROR_STATUS_LN0 0x3037
@@ -2178,5 +2183,8 @@ int drm_dp_pcon_dsc_bpp_incr(const u8
pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE
int drm_dp_pcon_pps_default(struct drm_dp_aux *aux); int
drm_dp_pcon_pps_override_buf(struct drm_dp_aux *aux, u8 pps_buf[128]); int
drm_dp_pcon_pps_override_param(struct drm_dp_aux *aux, u8 pps_param[6]);
+bool drm_dp_downstream_rgb_to_ycbcr_conversion(const u8
dpcd[DP_RECEIVER_CAP_SIZE],
+ const u8 port_cap[4]);
+int drm_dp_pcon_convert_rgb_to_ycbcr(struct drm_dp_aux *aux, u8
+color_spc);
#endif /* _DRM_DP_HELPER_H_ */
--
2.17.1
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