linux-kernel - [PATCH v2 3/4] drm/msm/dsi: Allow values of 10 and 12 for bits per component

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Message-ID: <20250217222431.82522-4-danila@jiaxyga.com>
Date: Tue, 18 Feb 2025 01:24:30 +0300
From: Danila Tikhonov <danila@...xyga.com>
To: neil.armstrong@...aro.org,
	quic_jesszhan@...cinc.com,
	maarten.lankhorst@...ux.intel.com,
	mripard@...nel.org,
	tzimmermann@...e.de,
	airlied@...il.com,
	simona@...ll.ch,
	robh@...nel.org,
	krzk+dt@...nel.org,
	conor+dt@...nel.org,
	andersson@...nel.org,
	konradybcio@...nel.org,
	robdclark@...il.com,
	quic_abhinavk@...cinc.com,
	dmitry.baryshkov@...aro.org,
	sean@...rly.run,
	marijn.suijten@...ainline.org,
	jonathan@...ek.ca,
	fekz115@...il.com
Cc: dri-devel@...ts.freedesktop.org,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-arm-msm@...r.kernel.org,
	freedreno@...ts.freedesktop.org,
	linux@...nlining.org,
	~postmarketos/upstreaming@...ts.sr.ht,
	Danila Tikhonov <danila@...xyga.com>
Subject: [PATCH v2 3/4] drm/msm/dsi: Allow values of 10 and 12 for bits per component

From: Eugene Lepshy <fekz115@...il.com>

The DRM DSC helper has various bits_per_component values - not just 8.
But the DSC 1.1 block supports only 8, 10, and 12. Extend the guard
accordingly and add a comment noting this limitation.

Signed-off-by: Eugene Lepshy <fekz115@...il.com>
Co-developed-by: Danila Tikhonov <danila@...xyga.com>
Signed-off-by: Danila Tikhonov <danila@...xyga.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
---
 drivers/gpu/drm/msm/dsi/dsi_host.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 007311c21fda..b9e247a23953 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -1767,8 +1767,20 @@ static int dsi_populate_dsc_params(struct msm_dsi_host *msm_host, struct drm_dsc
 		return -EINVAL;
 	}
 
-	if (dsc->bits_per_component != 8) {
-		DRM_DEV_ERROR(&msm_host->pdev->dev, "DSI does not support bits_per_component != 8 yet\n");
+	switch (dsc->bits_per_component) {
+	case 8:
+	case 10:
+	case 12:
+		/*
+		 * Only 8, 10, and 12 bpc are supported for DSC 1.1 block.
+		 * If additional bpc values need to be supported, update
+		 * this quard with the appropriate DSC version verification.
+		 */
+		break;
+	default:
+		DRM_DEV_ERROR(&msm_host->pdev->dev,
+			      "Unsupported bits_per_component value: %d\n",
+			      dsc->bits_per_component);
 		return -EOPNOTSUPP;
 	}
 
@@ -1779,7 +1791,7 @@ static int dsi_populate_dsc_params(struct msm_dsi_host *msm_host, struct drm_dsc
 	drm_dsc_set_const_params(dsc);
 	drm_dsc_set_rc_buf_thresh(dsc);
 
-	/* handle only bpp = bpc = 8, pre-SCR panels */
+	/* DPU supports only pre-SCR panels */
 	ret = drm_dsc_setup_rc_params(dsc, DRM_DSC_1_1_PRE_SCR);
 	if (ret) {
 		DRM_DEV_ERROR(&msm_host->pdev->dev, "could not find DSC RC parameters\n");
-- 
2.48.1