On 28-05-21, 13:29, Dmitry Baryshkov wrote:

On 21/05/2021 15:49, Vinod Koul wrote:

quoted

DSC needs some configuration from device tree, add support to read and
store these params and add DSC structures in msm_drv

Signed-off-by: Vinod Koul <vkoul@kernel.org>
---
  drivers/gpu/drm/msm/dsi/dsi_host.c | 170 +++++++++++++++++++++++++++++
  drivers/gpu/drm/msm/msm_drv.h      |  32 ++++++
  2 files changed, 202 insertions(+)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 8a10e4343281..864d3c655e73 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c

@@ -156,6 +156,7 @@ struct msm_dsi_host {
  	struct regmap *sfpb;
  	struct drm_display_mode *mode;
+	struct msm_display_dsc_config *dsc;
  	/* connected device info */
  	struct device_node *device_node;

@@ -1744,6 +1745,168 @@ static int dsi_host_parse_lane_data(struct msm_dsi_host *msm_host,
  	return -EINVAL;
  }
+static u32 dsi_dsc_rc_buf_thresh[DSC_NUM_BUF_RANGES - 1] = {
+	0x0e, 0x1c, 0x2a, 0x38, 0x46, 0x54, 0x62,
+	0x69, 0x70, 0x77, 0x79, 0x7b, 0x7d, 0x7e
+};

I think we should move this table to a generic place. AMD and Intel DSC code
uses the same table, shifted by 6 (and both of those drivers shift it before
writing to the HW). Intel modifies this table for 6bpp case. AMD seems to
use it as is.

quoted

+
+/* only 8bpc, 8bpp added */
+static char min_qp[DSC_NUM_BUF_RANGES] = {
+	0, 0, 1, 1, 3, 3, 3, 3, 3, 3, 5, 5, 5, 7, 13
+};
+
+static char max_qp[DSC_NUM_BUF_RANGES] = {
+	4, 4, 5, 6, 7, 7, 7, 8, 9, 10, 11, 12, 13, 13, 15
+};
+
+static char bpg_offset[DSC_NUM_BUF_RANGES] = {
+	2, 0, 0, -2, -4, -6, -8, -8, -8, -10, -10, -12, -12, -12, -12
+};

And these parameters seem to be generic too. Intel DSC code contains them in
a bit different form. Should we probably move them to the drm_dsc.c and use
the tables the generic location?

AMD drivers uses a bit different values at the first glance, so let's stick
with Intel version.

Yeah I think this is a good suggestion. I did look into and had this in
my todo. Yes drm_dsc.c would be apt for the move..

-- 
~Vinod