Re: [v8][PATCH 05/10] drm/i915/display: Extract i9xx_read_luts()

["Sharma, Swati2" <swati2.sharma@xxxxxxxxx>]

On 28-Aug-19 9:25 PM, Shankar, Uma wrote:

-----Original Message-----
From: Sharma, Swati2
Sent: Monday, August 26, 2019 11:56 AM
To: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: Nikula, Jani <jani.nikula@xxxxxxxxx>; Sharma, Shashank
<shashank.sharma@xxxxxxxxx>; Manna, Animesh <animesh.manna@xxxxxxxxx>;
Nautiyal, Ankit K <ankit.k.nautiyal@xxxxxxxxx>; daniel.vetter@xxxxxxxx;
ville.syrjala@xxxxxxxxxxxxxxx; Shankar, Uma <uma.shankar@xxxxxxxxx>; Sharma,
Swati2 <swati2.sharma@xxxxxxxxx>
Subject: [v8][PATCH 05/10] drm/i915/display: Extract i9xx_read_luts()

For the legacy gamma, have hw read out to create hw blob of gamma lut values.

Would be better if we define platforms for which this is applicable (I mean what all is
considered legacy here)

Also, add function intel_color_lut_pack to convert hw value with given bit_precision

Wrap this up within 75 characters.

to lut property val.

Keep the version history, don't drop that.

Signed-off-by: Swati Sharma <swati2.sharma@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_color.c | 51 ++++++++++++++++++++++++++++++
drivers/gpu/drm/i915/i915_reg.h            |  3 ++
2 files changed, 54 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_color.c
b/drivers/gpu/drm/i915/display/intel_color.c
index 27727a1..45e0ee8 100644
--- a/drivers/gpu/drm/i915/display/intel_color.c
+++ b/drivers/gpu/drm/i915/display/intel_color.c
@@ -1521,6 +1521,56 @@ bool intel_color_lut_equal(struct drm_property_blob
*blob1,
	return true;
}

+/* convert hw value with given bit_precision to lut property val */
+static u32 intel_color_lut_pack(u32 val, u32 bit_precision) {
+	u32 max = 0xffff >> (16 - bit_precision);
+
+	val = clamp_val(val, 0, max);
+
+	if (bit_precision < 16)
+		val <<= 16 - bit_precision;
+
+	return val;
+}
+
+static struct drm_property_blob *
+i9xx_read_lut_8(struct intel_crtc_state *crtc_state) {

Would be good to add some comments describing the rationale of this
function. Why 8 etc.

Func is written similar to load luts for i9xx.Therefore didn't explain 8.
Do I need to add comment for all the functions/platform? Won't commit message
sufficient enough?

+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
+	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+	enum pipe pipe = crtc->pipe;
+	struct drm_property_blob *blob;
+	struct drm_color_lut *blob_data;
+	u32 i, val;
+
+	blob = drm_property_create_blob(&dev_priv->drm,
+					sizeof(struct drm_color_lut) * 256,

Have a macro for 256. Explain why 256, add comments.

This is similar to load luts, since nothing new i added so didn't give
explanation. I can re-use LEGACY_LUT_LENGTH for this, since wanted these
functions to be similar to load_luts, therefore kept same.

+					NULL);
+	if (IS_ERR(blob))
+		return NULL;
+
+	blob_data = blob->data;
+
+	for (i = 0; i < 256; i++) {

Add the macro for 256.

Macro already there LEGACY_LUT_LENGTH. Should i reuse that?

+		if (HAS_GMCH(dev_priv))
+			val = I915_READ(PALETTE(pipe, i));
+		else
+			val = I915_READ(LGC_PALETTE(pipe, i));
+
+		blob_data[i].red =
intel_color_lut_pack(REG_FIELD_GET(LGC_PALETTE_RED_MASK, val), 8);
+		blob_data[i].green =
intel_color_lut_pack(REG_FIELD_GET(LGC_PALETTE_GREEN_MASK, val), 8);
+		blob_data[i].blue =
intel_color_lut_pack(REG_FIELD_GET(LGC_PALETTE_BLUE_MASK, val), 8);
+	}
+
+	return blob;
+}
+
+void i9xx_read_luts(struct intel_crtc_state *crtc_state) {
+	crtc_state->base.gamma_lut = i9xx_read_lut_8(crtc_state); }
+
void intel_color_init(struct intel_crtc *crtc)  {
	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev); @@ -1541,6
+1591,7 @@ void intel_color_init(struct intel_crtc *crtc)
			dev_priv->display.color_check = i9xx_color_check;
			dev_priv->display.color_commit = i9xx_color_commit;
			dev_priv->display.load_luts = i9xx_load_luts;
+			dev_priv->display.read_luts = i9xx_read_luts;
		}
	} else {
		if (INTEL_GEN(dev_priv) >= 11)
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index
a092b34..b687faa 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -7192,6 +7192,9 @@ enum {
/* legacy palette */
#define _LGC_PALETTE_A           0x4a000
#define _LGC_PALETTE_B           0x4a800
+#define LGC_PALETTE_RED_MASK     REG_GENMASK(23, 16)
+#define LGC_PALETTE_GREEN_MASK   REG_GENMASK(15, 8)
+#define LGC_PALETTE_BLUE_MASK    REG_GENMASK(7, 0)
#define LGC_PALETTE(pipe, i) _MMIO(_PIPE(pipe, _LGC_PALETTE_A,
_LGC_PALETTE_B) + (i) * 4)

/* ilk/snb precision palette */
--
1.9.1

-- 
~Swati Sharma

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