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From: Jessica Zhang <quic_jesszhan@quicinc.com>
To: Rob Clark <robdclark@gmail.com>,
	Abhinav Kumar <quic_abhinavk@quicinc.com>,
	Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
	Sean Paul <sean@poorly.run>, David Airlie <airlied@gmail.com>,
	Daniel Vetter <daniel@ffwll.ch>,
	Marijn Suijten <marijn.suijten@somainline.org>
Cc: Konrad Dybcio <konrad.dybcio@linaro.org>,
	<linux-arm-msm@vger.kernel.org>,
	<dri-devel@lists.freedesktop.org>,
	<freedreno@lists.freedesktop.org>, <linux-kernel@vger.kernel.org>,
	Jessica Zhang <quic_jesszhan@quicinc.com>
Subject: [PATCH v5 5/5] drm/msm/dsi: Remove incorrect references to slice_count
Date: Mon, 22 May 2023 18:08:59 -0700	[thread overview]
Message-ID: <20230405-add-dsc-support-v5-5-028c10850491@quicinc.com> (raw)
In-Reply-To: <20230405-add-dsc-support-v5-0-028c10850491@quicinc.com>

Currently, slice_count is being used to calculate word count and
pkt_per_line. Instead, these values should be calculated using slice per
packet, which is not the same as slice_count.

Slice count represents the number of slices per interface, and its value
will not always match that of slice per packet. For example, it is possible
to have cases where there are multiple slices per interface but the panel
specifies only one slice per packet.

Thus, use the default value of one slice per packet and remove slice_count
from the aforementioned calculations.

Fixes: 08802f515c3c ("drm/msm/dsi: Add support for DSC configuration")
Fixes: bc6b6ff8135c ("drm/msm/dsi: Use DSC slice(s) packet size to compute word count")
Reviewed-by: Marijn Suijten <marijn.suijten@somainline.org>
Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
---
 drivers/gpu/drm/msm/dsi/dsi_host.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 88f370dd2ea1..919760740bba 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -863,18 +863,17 @@ static void dsi_update_dsc_timing(struct msm_dsi_host *msm_host, bool is_cmd_mod
 	 */
 	slice_per_intf = msm_dsc_get_slices_per_intf(dsc, hdisplay);
 
-	/*
-	 * If slice_count is greater than slice_per_intf
-	 * then default to 1. This can happen during partial
-	 * update.
-	 */
-	if (dsc->slice_count > slice_per_intf)
-		dsc->slice_count = 1;
-
 	total_bytes_per_intf = dsc->slice_chunk_size * slice_per_intf;
 
 	eol_byte_num = total_bytes_per_intf % 3;
-	pkt_per_line = slice_per_intf / dsc->slice_count;
+
+	/*
+	 * Typically, pkt_per_line = slice_per_intf * slice_per_pkt.
+	 *
+	 * Since the current driver only supports slice_per_pkt = 1,
+	 * pkt_per_line will be equal to slice per intf for now.
+	 */
+	pkt_per_line = slice_per_intf;
 
 	if (is_cmd_mode) /* packet data type */
 		reg = DSI_COMMAND_COMPRESSION_MODE_CTRL_STREAM0_DATATYPE(MIPI_DSI_DCS_LONG_WRITE);
@@ -998,7 +997,14 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
 		if (!msm_host->dsc)
 			wc = hdisplay * dsi_get_bpp(msm_host->format) / 8 + 1;
 		else
-			wc = msm_host->dsc->slice_chunk_size * msm_host->dsc->slice_count + 1;
+			/*
+			 * When DSC is enabled, WC = slice_chunk_size * slice_per_pkt + 1.
+			 * Currently, the driver only supports default value of slice_per_pkt = 1
+			 *
+			 * TODO: Expand mipi_dsi_device struct to hold slice_per_pkt info
+			 *       and adjust DSC math to account for slice_per_pkt.
+			 */
+			wc = msm_host->dsc->slice_chunk_size + 1;
 
 		dsi_write(msm_host, REG_DSI_CMD_MDP_STREAM0_CTRL,
 			DSI_CMD_MDP_STREAM0_CTRL_WORD_COUNT(wc) |

-- 
2.40.1


      parent reply	other threads:[~2023-05-23  1:09 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-23  1:08 [PATCH v5 0/5] Add DSC v1.2 Support for DSI Jessica Zhang
2023-05-23  1:08 ` [PATCH v5 1/5] msm/drm/dsi: Round up DSC hdisplay calculation Jessica Zhang
2023-05-23  1:08 ` [PATCH v5 2/5] drm/msm/dsi: Adjust pclk rate for compression Jessica Zhang
2023-06-08 20:36   ` Marijn Suijten
2023-06-09  0:56     ` [Freedreno] " Jessica Zhang
2023-06-09  1:09       ` Abhinav Kumar
2023-06-11 21:19         ` Marijn Suijten
2023-06-11 21:59       ` Marijn Suijten
2023-06-09 16:58     ` Dmitry Baryshkov
2023-06-09 17:24       ` Jessica Zhang
2023-06-11 21:42       ` Marijn Suijten
2023-05-23  1:08 ` [PATCH v5 3/5] drm/msm/dpu: Add DPU_INTF_DATA_COMPRESS feature flag for DPU >= 7.0 Jessica Zhang
2023-05-23  1:08 ` [PATCH v5 4/5] drm/msm/dpu: Set DATA_COMPRESS on command mode for DCE/DSC 1.2 Jessica Zhang
2023-05-23  1:08 ` Jessica Zhang [this message]

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