This is a note to let you know that I've just added the patch titled

    drm/i915/display: Fix the 12 BPC bits for PIPE_MISC reg

to the 5.10-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-i915-display-fix-the-12-bpc-bits-for-pipe_misc-reg.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <sta...@vger.kernel.org> know about it.


>From abd9d66a055722393d33685214c08386694871d7 Mon Sep 17 00:00:00 2001
From: Ankit Nautiyal <ankit.k.nauti...@intel.com>
Date: Wed, 11 Aug 2021 10:48:57 +0530
Subject: drm/i915/display: Fix the 12 BPC bits for PIPE_MISC reg
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: Ankit Nautiyal <ankit.k.nauti...@intel.com>

commit abd9d66a055722393d33685214c08386694871d7 upstream.

Till DISPLAY12 the PIPE_MISC bits 5-7 are used to set the
Dithering BPC, with valid values of 6, 8, 10 BPC.
For ADLP+ these bits are used to set the PORT OUTPUT BPC, with valid
values of: 6, 8, 10, 12 BPC, and need to be programmed whether
dithering is enabled or not.

This patch:
-corrects the bits 5-7 for PIPE MISC register for 12 BPC.
-renames the bits and mask to have generic names for these bits for
dithering bpc and port output bpc.

v3: Added a note for MIPI DSI which uses the PIPE_MISC for readout
for pipe_bpp. (Uma Shankar)

v2: Added 'display' to the subject and fixes tag. (Uma Shankar)

Fixes: 756f85cffef2 ("drm/i915/bdw: Broadwell has PIPEMISC")
Cc: Paulo Zanoni <paulo.r.zan...@intel.com> (v1)
Cc: Ville Syrjälä <ville.syrj...@linux.intel.com>
Cc: Daniel Vetter <daniel.vet...@ffwll.ch>
Cc: Jani Nikula <jani.nik...@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahti...@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.v...@intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: <sta...@vger.kernel.org> # v3.13+

Signed-off-by: Ankit Nautiyal <ankit.k.nauti...@intel.com>
Reviewed-by: Uma Shankar <uma.shan...@intel.com>
Signed-off-by: Uma Shankar <uma.shan...@intel.com>
Link: 
https://patchwork.freedesktop.org/patch/msgid/20210811051857.109723-1-ankit.k.nauti...@intel.com
(cherry picked from commit 70418a68713c13da3f36c388087d0220b456a430)
Signed-off-by: Rodrigo Vivi <rodrigo.v...@intel.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/gpu/drm/i915/display/intel_display.c |   34 +++++++++++++++++++--------
 drivers/gpu/drm/i915/i915_reg.h              |   16 ++++++++----
 2 files changed, 35 insertions(+), 15 deletions(-)

--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -10173,16 +10173,18 @@ static void bdw_set_pipemisc(const struc
 
        switch (crtc_state->pipe_bpp) {
        case 18:
-               val |= PIPEMISC_DITHER_6_BPC;
+               val |= PIPEMISC_6_BPC;
                break;
        case 24:
-               val |= PIPEMISC_DITHER_8_BPC;
+               val |= PIPEMISC_8_BPC;
                break;
        case 30:
-               val |= PIPEMISC_DITHER_10_BPC;
+               val |= PIPEMISC_10_BPC;
                break;
        case 36:
-               val |= PIPEMISC_DITHER_12_BPC;
+               /* Port output 12BPC defined for ADLP+ */
+               if (DISPLAY_VER(dev_priv) > 12)
+                       val |= PIPEMISC_12_BPC_ADLP;
                break;
        default:
                MISSING_CASE(crtc_state->pipe_bpp);
@@ -10218,15 +10220,27 @@ int bdw_get_pipemisc_bpp(struct intel_cr
 
        tmp = intel_de_read(dev_priv, PIPEMISC(crtc->pipe));
 
-       switch (tmp & PIPEMISC_DITHER_BPC_MASK) {
-       case PIPEMISC_DITHER_6_BPC:
+       switch (tmp & PIPEMISC_BPC_MASK) {
+       case PIPEMISC_6_BPC:
                return 18;
-       case PIPEMISC_DITHER_8_BPC:
+       case PIPEMISC_8_BPC:
                return 24;
-       case PIPEMISC_DITHER_10_BPC:
+       case PIPEMISC_10_BPC:
                return 30;
-       case PIPEMISC_DITHER_12_BPC:
-               return 36;
+       /*
+        * PORT OUTPUT 12 BPC defined for ADLP+.
+        *
+        * TODO:
+        * For previous platforms with DSI interface, bits 5:7
+        * are used for storing pipe_bpp irrespective of dithering.
+        * Since the value of 12 BPC is not defined for these bits
+        * on older platforms, need to find a workaround for 12 BPC
+        * MIPI DSI HW readout.
+        */
+       case PIPEMISC_12_BPC_ADLP:
+               if (DISPLAY_VER(dev_priv) > 12)
+                       return 36;
+               fallthrough;
        default:
                MISSING_CASE(tmp);
                return 0;
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -6011,11 +6011,17 @@ enum {
 #define   PIPEMISC_HDR_MODE_PRECISION  (1 << 23) /* icl+ */
 #define   PIPEMISC_OUTPUT_COLORSPACE_YUV  (1 << 11)
 #define   PIPEMISC_PIXEL_ROUNDING_TRUNC        REG_BIT(8) /* tgl+ */
-#define   PIPEMISC_DITHER_BPC_MASK     (7 << 5)
-#define   PIPEMISC_DITHER_8_BPC                (0 << 5)
-#define   PIPEMISC_DITHER_10_BPC       (1 << 5)
-#define   PIPEMISC_DITHER_6_BPC                (2 << 5)
-#define   PIPEMISC_DITHER_12_BPC       (3 << 5)
+/*
+ * For Display < 13, Bits 5-7 of PIPE MISC represent DITHER BPC with
+ * valid values of: 6, 8, 10 BPC.
+ * ADLP+, the bits 5-7 represent PORT OUTPUT BPC with valid values of:
+ * 6, 8, 10, 12 BPC.
+ */
+#define   PIPEMISC_BPC_MASK            (7 << 5)
+#define   PIPEMISC_8_BPC               (0 << 5)
+#define   PIPEMISC_10_BPC              (1 << 5)
+#define   PIPEMISC_6_BPC               (2 << 5)
+#define   PIPEMISC_12_BPC_ADLP         (4 << 5) /* adlp+ */
 #define   PIPEMISC_DITHER_ENABLE       (1 << 4)
 #define   PIPEMISC_DITHER_TYPE_MASK    (3 << 2)
 #define   PIPEMISC_DITHER_TYPE_SP      (0 << 2)


Patches currently in stable-queue which might be from 
ankit.k.nauti...@intel.com are

queue-5.10/drm-i915-display-fix-the-12-bpc-bits-for-pipe_misc-reg.patch

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