drm/dp: Document DP spec versions for various DPCD registers

Note with a comment anything newer than DP 1.1a.

Obviously this needs some work still...

Signed-off-by: Adam Jackson <ajax@redhat.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 32 insertions, 20 deletions

diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index f9888c3cb955..38ffcb4332aa 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -26,7 +26,19 @@
 #include <linux/types.h>
 #include <linux/i2c.h>
 
-/* From the VESA DisplayPort spec */
+/*
+ * Unless otherwise noted, all values are from the DP 1.1a spec.  Note that
+ * DP and DPCD versions are independent.  Differences from 1.0 are not noted,
+ * 1.0 devices basically don't exist in the wild.
+ *
+ * Abbreviations, in chronological order:
+ *
+ * eDP: Embedded DisplayPort version 1
+ * DPI: DisplayPort Interoperability Guideline v1.1a
+ * 1.2: DisplayPort 1.2
+ *
+ * 1.2 formally includes both eDP and DPI definitions.
+ */
 
 #define AUX_NATIVE_WRITE        0x8
 #define AUX_NATIVE_READ         0x9
@@ -53,7 +65,7 @@
 
 #define DP_MAX_LANE_COUNT                   0x002
 # define DP_MAX_LANE_COUNT_MASK             0x1f
-# define DP_TPS3_SUPPORTED                  (1 << 6)
+# define DP_TPS3_SUPPORTED                  (1 << 6) /* 1.2 */
 # define DP_ENHANCED_FRAME_CAP              (1 << 7)
 
 #define DP_MAX_DOWNSPREAD                   0x003
@@ -69,16 +81,16 @@
 /* 10b = TMDS or HDMI */
 /* 11b = Other */
 # define DP_FORMAT_CONVERSION               (1 << 3)
-# define DP_DETAILED_CAP_INFO_AVAILABLE     (1 << 4)
+# define DP_DETAILED_CAP_INFO_AVAILABLE     (1 << 4) /* DPI */
 
 #define DP_MAIN_LINK_CHANNEL_CODING         0x006
 
 #define DP_DOWN_STREAM_PORT_COUNT           0x007
 # define DP_PORT_COUNT_MASK                 0x0f
-# define DP_MSA_TIMING_PAR_IGNORED          (1 << 6)
+# define DP_MSA_TIMING_PAR_IGNORED          (1 << 6) /* eDP */
 # define DP_OUI_SUPPORT                     (1 << 7)
 
-#define DP_I2C_SPEED_CAP                    0x00c
+#define DP_I2C_SPEED_CAP                    0x00c    /* DPI */
 # define DP_I2C_SPEED_1K                    0x01
 # define DP_I2C_SPEED_5K                    0x02
 # define DP_I2C_SPEED_10K                   0x04
@@ -86,16 +98,16 @@
 # define DP_I2C_SPEED_400K                  0x10
 # define DP_I2C_SPEED_1M                    0x20
 
-#define DP_EDP_CONFIGURATION_CAP            0x00d
-#define DP_TRAINING_AUX_RD_INTERVAL         0x00e
+#define DP_EDP_CONFIGURATION_CAP            0x00d   /* XXX 1.2? */
+#define DP_TRAINING_AUX_RD_INTERVAL         0x00e   /* XXX 1.2? */
 
 /* Multiple stream transport */
-#define DP_MSTM_CAP                         0x021
+#define DP_MSTM_CAP                         0x021   /* 1.2 */
 # define DP_MST_CAP                         (1 << 0)
 
-#define DP_PSR_SUPPORT                      0x070
+#define DP_PSR_SUPPORT                      0x070   /* XXX 1.2? */
 # define DP_PSR_IS_SUPPORTED                1
-#define DP_PSR_CAPS                         0x071
+#define DP_PSR_CAPS                         0x071   /* XXX 1.2? */
 # define DP_PSR_NO_TRAIN_ON_EXIT            1
 # define DP_PSR_SETUP_TIME_330              (0 << 1)
 # define DP_PSR_SETUP_TIME_275              (1 << 1)
@@ -136,7 +148,7 @@
 #define DP_LINK_BW_SET                      0x100
 # define DP_LINK_BW_1_62                    0x06
 # define DP_LINK_BW_2_7                     0x0a
-# define DP_LINK_BW_5_4                     0x14
+# define DP_LINK_BW_5_4                     0x14    /* 1.2 */
 
 #define DP_LANE_COUNT_SET                   0x101
 # define DP_LANE_COUNT_MASK                 0x0f
@@ -146,7 +158,7 @@
 # define DP_TRAINING_PATTERN_DISABLE        0
 # define DP_TRAINING_PATTERN_1              1
 # define DP_TRAINING_PATTERN_2              2
-# define DP_TRAINING_PATTERN_3              3
+# define DP_TRAINING_PATTERN_3              3       /* 1.2 */
 # define DP_TRAINING_PATTERN_MASK           0x3
 
 # define DP_LINK_QUAL_PATTERN_DISABLE       (0 << 2)
@@ -187,22 +199,22 @@
 
 #define DP_DOWNSPREAD_CTRL                  0x107
 # define DP_SPREAD_AMP_0_5                  (1 << 4)
-# define DP_MSA_TIMING_PAR_IGNORE_EN        (1 << 7)
+# define DP_MSA_TIMING_PAR_IGNORE_EN        (1 << 7) /* eDP */
 
 #define DP_MAIN_LINK_CHANNEL_CODING_SET     0x108
 # define DP_SET_ANSI_8B10B                  (1 << 0)
 
-#define DP_I2C_SPEED_CONTROL_STATUS         0x109
+#define DP_I2C_SPEED_CONTROL_STATUS         0x109   /* DPI */
 /* bitmask as for DP_I2C_SPEED_CAP */
 
-#define DP_EDP_CONFIGURATION_SET            0x10a
+#define DP_EDP_CONFIGURATION_SET            0x10a   /* XXX 1.2? */
 
-#define DP_MSTM_CTRL                        0x111
+#define DP_MSTM_CTRL                        0x111   /* 1.2 */
 # define DP_MST_EN                          (1 << 0)
 # define DP_UP_REQ_EN                       (1 << 1)
 # define DP_UPSTREAM_IS_SRC                 (1 << 2)
 
-#define DP_PSR_EN_CFG                       0x170
+#define DP_PSR_EN_CFG                       0x170   /* XXX 1.2? */
 # define DP_PSR_ENABLE                      (1 << 0)
 # define DP_PSR_MAIN_LINK_ACTIVE            (1 << 1)
 # define DP_PSR_CRC_VERIFICATION            (1 << 2)
@@ -277,14 +289,14 @@
 # define DP_SET_POWER_D0                    0x1
 # define DP_SET_POWER_D3                    0x2
 
-#define DP_PSR_ERROR_STATUS                 0x2006
+#define DP_PSR_ERROR_STATUS                 0x2006  /* XXX 1.2? */
 # define DP_PSR_LINK_CRC_ERROR              (1 << 0)
 # define DP_PSR_RFB_STORAGE_ERROR           (1 << 1)
 
-#define DP_PSR_ESI                          0x2007
+#define DP_PSR_ESI                          0x2007  /* XXX 1.2? */
 # define DP_PSR_CAPS_CHANGE                 (1 << 0)
 
-#define DP_PSR_STATUS                       0x2008
+#define DP_PSR_STATUS                       0x2008  /* XXX 1.2? */
 # define DP_PSR_SINK_INACTIVE               0
 # define DP_PSR_SINK_ACTIVE_SRC_SYNCED      1
 # define DP_PSR_SINK_ACTIVE_RFB             2