diff mbox series

[2/8] drm/i915/display: Store compressed bpp in U6.4 format

Message ID 20230929071322.945521-3-mitulkumar.ajitkumar.golani@intel.com (mailing list archive)
State New, archived
Headers show
Series Add DSC fractional bpp support | expand

Commit Message

Golani, Mitulkumar Ajitkumar Sept. 29, 2023, 7:13 a.m. UTC
From: Ankit Nautiyal <ankit.k.nautiyal@intel.com>

DSC parameter bits_per_pixel is stored in U6.4 format.
The 4 bits represent the fractional part of the bpp.
Currently we use compressed_bpp member of dsc structure to store
only the integral part of the bits_per_pixel.
To store the full bits_per_pixel along with the fractional part,
compressed_bpp is changed to store bpp in U6.4 formats. Intergral
part is retrieved by simply right shifting the member compressed_bpp by 4.

v2:
-Use to_bpp_int, to_bpp_frac_dec, to_bpp_x16 helpers while dealing
 with compressed bpp. (Suraj)
-Fix comment styling. (Suraj)

v3:
-Add separate file for 6.4 fixed point helper(Jani, Nikula)
-Add comment for magic values(Suraj)

v4:
Fix checkpatch warnings caused by renaming(Suraj)

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Sui Jingfeng <suijingfeng@loongson.cn>
---
 drivers/gpu/drm/i915/display/icl_dsi.c        | 11 +++---
 drivers/gpu/drm/i915/display/intel_audio.c    |  3 +-
 drivers/gpu/drm/i915/display/intel_bios.c     |  6 ++--
 drivers/gpu/drm/i915/display/intel_cdclk.c    |  6 ++--
 drivers/gpu/drm/i915/display/intel_display.c  |  2 +-
 .../drm/i915/display/intel_display_types.h    |  3 +-
 drivers/gpu/drm/i915/display/intel_dp.c       | 33 ++++++++++-------
 drivers/gpu/drm/i915/display/intel_dp_mst.c   | 26 ++++++++------
 .../i915/display/intel_fractional_helper.h    | 36 +++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_vdsc.c     |  5 +--
 10 files changed, 93 insertions(+), 38 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/display/intel_fractional_helper.h

Comments

kernel test robot Sept. 30, 2023, 5:41 a.m. UTC | #1
Hi Mitul,

kernel test robot noticed the following build errors:

[auto build test ERROR on drm-tip/drm-tip]

url:    https://github.com/intel-lab-lkp/linux/commits/Mitul-Golani/drm-display-dp-Add-helper-function-to-get-DSC-bpp-precision/20230929-162949
base:   git://anongit.freedesktop.org/drm/drm-tip drm-tip
patch link:    https://lore.kernel.org/r/20230929071322.945521-3-mitulkumar.ajitkumar.golani%40intel.com
patch subject: [PATCH 2/8] drm/i915/display: Store compressed bpp in U6.4 format
config: x86_64-rhel-8.3-kselftests (https://download.01.org/0day-ci/archive/20230930/202309301303.ujZmUWZH-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230930/202309301303.ujZmUWZH-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202309301303.ujZmUWZH-lkp@intel.com/

All errors (new ones prefixed by >>):

   drivers/gpu/drm/i915/display/intel_link_bw.c: In function 'intel_link_bw_reduce_bpp':
>> drivers/gpu/drm/i915/display/intel_link_bw.c:71:52: error: 'struct <anonymous>' has no member named 'compressed_bpp'; did you mean 'compressed_bpp_x16'?
      71 |                         link_bpp = crtc_state->dsc.compressed_bpp;
         |                                                    ^~~~~~~~~~~~~~
         |                                                    compressed_bpp_x16


vim +71 drivers/gpu/drm/i915/display/intel_link_bw.c

8ca0b875c08258 Imre Deak 2023-09-21  28  
8ca0b875c08258 Imre Deak 2023-09-21  29  /**
8ca0b875c08258 Imre Deak 2023-09-21  30   * intel_link_bw_reduce_bpp - reduce maximum link bpp for a selected pipe
8ca0b875c08258 Imre Deak 2023-09-21  31   * @state: atomic state
8ca0b875c08258 Imre Deak 2023-09-21  32   * @limits: link BW limits
8ca0b875c08258 Imre Deak 2023-09-21  33   * @pipe_mask: mask of pipes to select from
8ca0b875c08258 Imre Deak 2023-09-21  34   * @reason: explanation of why bpp reduction is needed
8ca0b875c08258 Imre Deak 2023-09-21  35   *
8ca0b875c08258 Imre Deak 2023-09-21  36   * Select the pipe from @pipe_mask with the biggest link bpp value and set the
8ca0b875c08258 Imre Deak 2023-09-21  37   * maximum of link bpp in @limits below this value. Modeset the selected pipe,
8ca0b875c08258 Imre Deak 2023-09-21  38   * so that its state will get recomputed.
8ca0b875c08258 Imre Deak 2023-09-21  39   *
8ca0b875c08258 Imre Deak 2023-09-21  40   * This function can be called to resolve a link's BW overallocation by reducing
8ca0b875c08258 Imre Deak 2023-09-21  41   * the link bpp of one pipe on the link and hence reducing the total link BW.
8ca0b875c08258 Imre Deak 2023-09-21  42   *
8ca0b875c08258 Imre Deak 2023-09-21  43   * Returns
8ca0b875c08258 Imre Deak 2023-09-21  44   *   - 0 in case of success
8ca0b875c08258 Imre Deak 2023-09-21  45   *   - %-ENOSPC if no pipe can further reduce its link bpp
8ca0b875c08258 Imre Deak 2023-09-21  46   *   - Other negative error, if modesetting the selected pipe failed
8ca0b875c08258 Imre Deak 2023-09-21  47   */
8ca0b875c08258 Imre Deak 2023-09-21  48  int intel_link_bw_reduce_bpp(struct intel_atomic_state *state,
8ca0b875c08258 Imre Deak 2023-09-21  49  			     struct intel_link_bw_limits *limits,
8ca0b875c08258 Imre Deak 2023-09-21  50  			     u8 pipe_mask,
8ca0b875c08258 Imre Deak 2023-09-21  51  			     const char *reason)
8ca0b875c08258 Imre Deak 2023-09-21  52  {
8ca0b875c08258 Imre Deak 2023-09-21  53  	struct drm_i915_private *i915 = to_i915(state->base.dev);
8ca0b875c08258 Imre Deak 2023-09-21  54  	enum pipe max_bpp_pipe = INVALID_PIPE;
8ca0b875c08258 Imre Deak 2023-09-21  55  	struct intel_crtc *crtc;
8ca0b875c08258 Imre Deak 2023-09-21  56  	int max_bpp = 0;
8ca0b875c08258 Imre Deak 2023-09-21  57  
8ca0b875c08258 Imre Deak 2023-09-21  58  	for_each_intel_crtc_in_pipe_mask(&i915->drm, crtc, pipe_mask) {
8ca0b875c08258 Imre Deak 2023-09-21  59  		struct intel_crtc_state *crtc_state;
8ca0b875c08258 Imre Deak 2023-09-21  60  		int link_bpp;
8ca0b875c08258 Imre Deak 2023-09-21  61  
8ca0b875c08258 Imre Deak 2023-09-21  62  		if (limits->bpp_limit_reached_pipes & BIT(crtc->pipe))
8ca0b875c08258 Imre Deak 2023-09-21  63  			continue;
8ca0b875c08258 Imre Deak 2023-09-21  64  
8ca0b875c08258 Imre Deak 2023-09-21  65  		crtc_state = intel_atomic_get_crtc_state(&state->base,
8ca0b875c08258 Imre Deak 2023-09-21  66  							 crtc);
8ca0b875c08258 Imre Deak 2023-09-21  67  		if (IS_ERR(crtc_state))
8ca0b875c08258 Imre Deak 2023-09-21  68  			return PTR_ERR(crtc_state);
8ca0b875c08258 Imre Deak 2023-09-21  69  
8ca0b875c08258 Imre Deak 2023-09-21  70  		if (crtc_state->dsc.compression_enable)
8ca0b875c08258 Imre Deak 2023-09-21 @71  			link_bpp = crtc_state->dsc.compressed_bpp;
8ca0b875c08258 Imre Deak 2023-09-21  72  		else
8ca0b875c08258 Imre Deak 2023-09-21  73  			/*
8ca0b875c08258 Imre Deak 2023-09-21  74  			 * TODO: for YUV420 the actual link bpp is only half
8ca0b875c08258 Imre Deak 2023-09-21  75  			 * of the pipe bpp value. The MST encoder's BW allocation
8ca0b875c08258 Imre Deak 2023-09-21  76  			 * is based on the pipe bpp value, set the actual link bpp
8ca0b875c08258 Imre Deak 2023-09-21  77  			 * limit here once the MST BW allocation is fixed.
8ca0b875c08258 Imre Deak 2023-09-21  78  			 */
8ca0b875c08258 Imre Deak 2023-09-21  79  			link_bpp = crtc_state->pipe_bpp;
8ca0b875c08258 Imre Deak 2023-09-21  80  
8ca0b875c08258 Imre Deak 2023-09-21  81  		if (link_bpp > max_bpp) {
8ca0b875c08258 Imre Deak 2023-09-21  82  			max_bpp = link_bpp;
8ca0b875c08258 Imre Deak 2023-09-21  83  			max_bpp_pipe = crtc->pipe;
8ca0b875c08258 Imre Deak 2023-09-21  84  		}
8ca0b875c08258 Imre Deak 2023-09-21  85  	}
8ca0b875c08258 Imre Deak 2023-09-21  86  
8ca0b875c08258 Imre Deak 2023-09-21  87  	if (max_bpp_pipe == INVALID_PIPE)
8ca0b875c08258 Imre Deak 2023-09-21  88  		return -ENOSPC;
8ca0b875c08258 Imre Deak 2023-09-21  89  
8ca0b875c08258 Imre Deak 2023-09-21  90  	limits->max_bpp_x16[max_bpp_pipe] = to_bpp_x16(max_bpp) - 1;
8ca0b875c08258 Imre Deak 2023-09-21  91  
8ca0b875c08258 Imre Deak 2023-09-21  92  	return intel_modeset_pipes_in_mask_early(state, reason,
8ca0b875c08258 Imre Deak 2023-09-21  93  						 BIT(max_bpp_pipe));
8ca0b875c08258 Imre Deak 2023-09-21  94  }
8ca0b875c08258 Imre Deak 2023-09-21  95
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/display/icl_dsi.c b/drivers/gpu/drm/i915/display/icl_dsi.c
index c4585e445198..77b73bd61076 100644
--- a/drivers/gpu/drm/i915/display/icl_dsi.c
+++ b/drivers/gpu/drm/i915/display/icl_dsi.c
@@ -43,6 +43,7 @@ 
 #include "intel_de.h"
 #include "intel_dsi.h"
 #include "intel_dsi_vbt.h"
+#include "intel_fractional_helper.h"
 #include "intel_panel.h"
 #include "intel_vdsc.h"
 #include "intel_vdsc_regs.h"
@@ -330,7 +331,7 @@  static int afe_clk(struct intel_encoder *encoder,
 	int bpp;
 
 	if (crtc_state->dsc.compression_enable)
-		bpp = crtc_state->dsc.compressed_bpp;
+		bpp = intel_fractional_bpp_from_x16(crtc_state->dsc.compressed_bpp_x16);
 	else
 		bpp = mipi_dsi_pixel_format_to_bpp(intel_dsi->pixel_format);
 
@@ -860,7 +861,7 @@  gen11_dsi_set_transcoder_timings(struct intel_encoder *encoder,
 	 * compressed and non-compressed bpp.
 	 */
 	if (crtc_state->dsc.compression_enable) {
-		mul = crtc_state->dsc.compressed_bpp;
+		mul = intel_fractional_bpp_from_x16(crtc_state->dsc.compressed_bpp_x16);
 		div = mipi_dsi_pixel_format_to_bpp(intel_dsi->pixel_format);
 	}
 
@@ -884,7 +885,7 @@  gen11_dsi_set_transcoder_timings(struct intel_encoder *encoder,
 		int bpp, line_time_us, byte_clk_period_ns;
 
 		if (crtc_state->dsc.compression_enable)
-			bpp = crtc_state->dsc.compressed_bpp;
+			bpp = intel_fractional_bpp_from_x16(crtc_state->dsc.compressed_bpp_x16);
 		else
 			bpp = mipi_dsi_pixel_format_to_bpp(intel_dsi->pixel_format);
 
@@ -1451,8 +1452,8 @@  static void gen11_dsi_get_timings(struct intel_encoder *encoder,
 	struct drm_display_mode *adjusted_mode =
 					&pipe_config->hw.adjusted_mode;
 
-	if (pipe_config->dsc.compressed_bpp) {
-		int div = pipe_config->dsc.compressed_bpp;
+	if (pipe_config->dsc.compressed_bpp_x16) {
+		int div = intel_fractional_bpp_from_x16(pipe_config->dsc.compressed_bpp_x16);
 		int mul = mipi_dsi_pixel_format_to_bpp(intel_dsi->pixel_format);
 
 		adjusted_mode->crtc_htotal =
diff --git a/drivers/gpu/drm/i915/display/intel_audio.c b/drivers/gpu/drm/i915/display/intel_audio.c
index 19605264a35c..4f1db1581316 100644
--- a/drivers/gpu/drm/i915/display/intel_audio.c
+++ b/drivers/gpu/drm/i915/display/intel_audio.c
@@ -35,6 +35,7 @@ 
 #include "intel_crtc.h"
 #include "intel_de.h"
 #include "intel_display_types.h"
+#include "intel_fractional_helper.h"
 #include "intel_lpe_audio.h"
 
 /**
@@ -528,7 +529,7 @@  static unsigned int calc_hblank_early_prog(struct intel_encoder *encoder,
 	h_active = crtc_state->hw.adjusted_mode.crtc_hdisplay;
 	h_total = crtc_state->hw.adjusted_mode.crtc_htotal;
 	pixel_clk = crtc_state->hw.adjusted_mode.crtc_clock;
-	vdsc_bpp = crtc_state->dsc.compressed_bpp;
+	vdsc_bpp = intel_fractional_bpp_from_x16(crtc_state->dsc.compressed_bpp_x16);
 	cdclk = i915->display.cdclk.hw.cdclk;
 	/* fec= 0.972261, using rounding multiplier of 1000000 */
 	fec_coeff = 972261;
diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
index 4e8f1e91bb08..616492a1a7ef 100644
--- a/drivers/gpu/drm/i915/display/intel_bios.c
+++ b/drivers/gpu/drm/i915/display/intel_bios.c
@@ -33,6 +33,7 @@ 
 #include "i915_reg.h"
 #include "intel_display.h"
 #include "intel_display_types.h"
+#include "intel_fractional_helper.h"
 #include "intel_gmbus.h"
 
 #define _INTEL_BIOS_PRIVATE
@@ -3392,8 +3393,9 @@  static void fill_dsc(struct intel_crtc_state *crtc_state,
 
 	crtc_state->pipe_bpp = bpc * 3;
 
-	crtc_state->dsc.compressed_bpp = min(crtc_state->pipe_bpp,
-					     VBT_DSC_MAX_BPP(dsc->max_bpp));
+	crtc_state->dsc.compressed_bpp_x16 =
+		intel_fractional_bpp_to_x16(min(crtc_state->pipe_bpp,
+						VBT_DSC_MAX_BPP(dsc->max_bpp)));
 
 	/*
 	 * FIXME: This is ugly, and slice count should take DSC engine
diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c
index 6d7ba4d0f130..d62a93ed39dd 100644
--- a/drivers/gpu/drm/i915/display/intel_cdclk.c
+++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
@@ -34,6 +34,7 @@ 
 #include "intel_de.h"
 #include "intel_dp.h"
 #include "intel_display_types.h"
+#include "intel_fractional_helper.h"
 #include "intel_mchbar_regs.h"
 #include "intel_pci_config.h"
 #include "intel_pcode.h"
@@ -2598,8 +2599,9 @@  static int intel_vdsc_min_cdclk(const struct intel_crtc_state *crtc_state)
 		 * => CDCLK >= compressed_bpp * Pixel clock  / 2 * Bigjoiner Interface bits
 		 */
 		int bigjoiner_interface_bits = DISPLAY_VER(i915) > 13 ? 36 : 24;
-		int min_cdclk_bj = (crtc_state->dsc.compressed_bpp * pixel_clock) /
-				   (2 * bigjoiner_interface_bits);
+		int min_cdclk_bj =
+			(intel_fractional_bpp_from_x16(crtc_state->dsc.compressed_bpp_x16) *
+			 pixel_clock) / (2 * bigjoiner_interface_bits);
 
 		min_cdclk = max(min_cdclk, min_cdclk_bj);
 	}
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index b3ae81a6ab16..01cc22e97460 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -5415,7 +5415,7 @@  intel_pipe_config_compare(const struct intel_crtc_state *current_config,
 
 	PIPE_CONF_CHECK_I(dsc.compression_enable);
 	PIPE_CONF_CHECK_I(dsc.dsc_split);
-	PIPE_CONF_CHECK_I(dsc.compressed_bpp);
+	PIPE_CONF_CHECK_I(dsc.compressed_bpp_x16);
 
 	PIPE_CONF_CHECK_BOOL(splitter.enable);
 	PIPE_CONF_CHECK_I(splitter.link_count);
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 8d8b2f8d37a9..19da97584afa 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1355,7 +1355,8 @@  struct intel_crtc_state {
 	struct {
 		bool compression_enable;
 		bool dsc_split;
-		u16 compressed_bpp;
+		/* Compressed Bpp in U6.4 format (first 4 bits for fractional part) */
+		u16 compressed_bpp_x16;
 		u8 slice_count;
 		struct drm_dsc_config config;
 	} dsc;
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 11420595c4f9..15de7940a433 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -64,6 +64,7 @@ 
 #include "intel_dp_mst.h"
 #include "intel_dpio_phy.h"
 #include "intel_dpll.h"
+#include "intel_fractional_helper.h"
 #include "intel_fifo_underrun.h"
 #include "intel_hdcp.h"
 #include "intel_hdmi.h"
@@ -1865,7 +1866,8 @@  icl_dsc_compute_link_config(struct intel_dp *intel_dp,
 					      valid_dsc_bpp[i],
 					      timeslots);
 		if (ret == 0) {
-			pipe_config->dsc.compressed_bpp = valid_dsc_bpp[i];
+			pipe_config->dsc.compressed_bpp_x16 =
+				intel_fractional_bpp_to_x16(valid_dsc_bpp[i]);
 			return 0;
 		}
 	}
@@ -1903,7 +1905,8 @@  xelpd_dsc_compute_link_config(struct intel_dp *intel_dp,
 					      compressed_bpp,
 					      timeslots);
 		if (ret == 0) {
-			pipe_config->dsc.compressed_bpp = compressed_bpp;
+			pipe_config->dsc.compressed_bpp_x16 =
+				intel_fractional_bpp_to_x16(compressed_bpp);
 			return 0;
 		}
 	}
@@ -2091,7 +2094,8 @@  static int intel_edp_dsc_compute_pipe_bpp(struct intel_dp *intel_dp,
 	/* Compressed BPP should be less than the Input DSC bpp */
 	dsc_max_bpp = min(dsc_max_bpp, pipe_bpp - 1);
 
-	pipe_config->dsc.compressed_bpp = max(dsc_min_bpp, dsc_max_bpp);
+	pipe_config->dsc.compressed_bpp_x16 =
+		intel_fractional_bpp_to_x16(max(dsc_min_bpp, dsc_max_bpp));
 
 	pipe_config->pipe_bpp = pipe_bpp;
 
@@ -2177,18 +2181,19 @@  int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
 	ret = intel_dp_dsc_compute_params(&dig_port->base, pipe_config);
 	if (ret < 0) {
 		drm_dbg_kms(&dev_priv->drm,
-			    "Cannot compute valid DSC parameters for Input Bpp = %d "
-			    "Compressed BPP = %d\n",
+			    "Cannot compute valid DSC parameters for Input Bpp = %d Compressed BPP = %d.%d\n",
 			    pipe_config->pipe_bpp,
-			    pipe_config->dsc.compressed_bpp);
+			    intel_fractional_bpp_from_x16(pipe_config->dsc.compressed_bpp_x16),
+			    intel_fractional_bpp_decimal(pipe_config->dsc.compressed_bpp_x16));
 		return ret;
 	}
 
 	pipe_config->dsc.compression_enable = true;
-	drm_dbg_kms(&dev_priv->drm, "DP DSC computed with Input Bpp = %d "
-		    "Compressed Bpp = %d Slice Count = %d\n",
+	drm_dbg_kms(&dev_priv->drm,
+		    "DP DSC computed with Input Bpp = %d Compressed Bpp = %d.%d Slice Count = %d\n",
 		    pipe_config->pipe_bpp,
-		    pipe_config->dsc.compressed_bpp,
+		    intel_fractional_bpp_from_x16(pipe_config->dsc.compressed_bpp_x16),
+		    intel_fractional_bpp_decimal(pipe_config->dsc.compressed_bpp_x16),
 		    pipe_config->dsc.slice_count);
 
 	return 0;
@@ -2355,15 +2360,17 @@  intel_dp_compute_link_config(struct intel_encoder *encoder,
 
 	if (pipe_config->dsc.compression_enable) {
 		drm_dbg_kms(&i915->drm,
-			    "DP lane count %d clock %d Input bpp %d Compressed bpp %d\n",
+			    "DP lane count %d clock %d Input bpp %d Compressed bpp %d.%d\n",
 			    pipe_config->lane_count, pipe_config->port_clock,
 			    pipe_config->pipe_bpp,
-			    pipe_config->dsc.compressed_bpp);
+			    intel_fractional_bpp_from_x16(pipe_config->dsc.compressed_bpp_x16),
+			    intel_fractional_bpp_decimal(pipe_config->dsc.compressed_bpp_x16));
 
 		drm_dbg_kms(&i915->drm,
 			    "DP link rate required %i available %i\n",
 			    intel_dp_link_required(adjusted_mode->crtc_clock,
-						   pipe_config->dsc.compressed_bpp),
+						   intel_fractional_bpp_from_x16
+						   (pipe_config->dsc.compressed_bpp_x16)),
 			    intel_dp_max_data_rate(pipe_config->port_clock,
 						   pipe_config->lane_count));
 	} else {
@@ -2799,7 +2806,7 @@  intel_dp_compute_config(struct intel_encoder *encoder,
 		drm_dp_enhanced_frame_cap(intel_dp->dpcd);
 
 	if (pipe_config->dsc.compression_enable)
-		link_bpp = pipe_config->dsc.compressed_bpp;
+		link_bpp = pipe_config->dsc.compressed_bpp_x16;
 	else
 		link_bpp = intel_dp_output_bpp(pipe_config->output_format,
 					       pipe_config->pipe_bpp);
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 648cf37e02a8..cb189b930b5b 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -41,6 +41,7 @@ 
 #include "intel_dp_hdcp.h"
 #include "intel_dp_mst.h"
 #include "intel_dpio_phy.h"
+#include "intel_fractional_helper.h"
 #include "intel_hdcp.h"
 #include "intel_hotplug.h"
 #include "skl_scaler.h"
@@ -140,7 +141,7 @@  static int intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder,
 		if (!dsc)
 			crtc_state->pipe_bpp = bpp;
 		else
-			crtc_state->dsc.compressed_bpp = bpp;
+			crtc_state->dsc.compressed_bpp_x16 = intel_fractional_bpp_to_x16(bpp);
 		drm_dbg_kms(&i915->drm, "Got %d slots for pipe bpp %d dsc %d\n", slots, bpp, dsc);
 	}
 
@@ -247,13 +248,14 @@  static int intel_dp_dsc_mst_compute_link_config(struct intel_encoder *encoder,
 	if (slots < 0)
 		return slots;
 
-	last_compressed_bpp = crtc_state->dsc.compressed_bpp;
+	last_compressed_bpp = intel_fractional_bpp_from_x16(crtc_state->dsc.compressed_bpp_x16);
 
-	crtc_state->dsc.compressed_bpp = intel_dp_dsc_nearest_valid_bpp(i915,
-									last_compressed_bpp,
-									crtc_state->pipe_bpp);
+	crtc_state->dsc.compressed_bpp_x16 =
+		intel_fractional_bpp_to_x16(intel_dp_dsc_nearest_valid_bpp(i915,
+									   last_compressed_bpp,
+									   crtc_state->pipe_bpp));
 
-	if (crtc_state->dsc.compressed_bpp != last_compressed_bpp)
+	if (crtc_state->dsc.compressed_bpp_x16 != intel_fractional_bpp_to_x16(last_compressed_bpp))
 		need_timeslot_recalc = true;
 
 	/*
@@ -261,15 +263,17 @@  static int intel_dp_dsc_mst_compute_link_config(struct intel_encoder *encoder,
 	 * the actual compressed bpp we use.
 	 */
 	if (need_timeslot_recalc) {
-		slots = intel_dp_mst_find_vcpi_slots_for_bpp(encoder, crtc_state,
-							     crtc_state->dsc.compressed_bpp,
-							     crtc_state->dsc.compressed_bpp,
-							     limits, conn_state, 2 * 3, true);
+		slots =
+		intel_dp_mst_find_vcpi_slots_for_bpp(encoder, crtc_state,
+						     intel_fractional_bpp_from_x16
+						     (crtc_state->dsc.compressed_bpp_x16),
+		intel_fractional_bpp_from_x16(crtc_state->dsc.compressed_bpp_x16),
+		limits, conn_state, 2 * 3, true);
 		if (slots < 0)
 			return slots;
 	}
 
-	intel_link_compute_m_n(crtc_state->dsc.compressed_bpp,
+	intel_link_compute_m_n(intel_fractional_bpp_from_x16(crtc_state->dsc.compressed_bpp_x16),
 			       crtc_state->lane_count,
 			       adjusted_mode->crtc_clock,
 			       crtc_state->port_clock,
diff --git a/drivers/gpu/drm/i915/display/intel_fractional_helper.h b/drivers/gpu/drm/i915/display/intel_fractional_helper.h
new file mode 100644
index 000000000000..0212a9041c8f
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_fractional_helper.h
@@ -0,0 +1,36 @@ 
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2023 Intel Corporation
+ */
+#ifndef __INTEL_FRACTIONAL_HELPERS_H__
+#define __INTEL_FRACTIONAL_HELPERS_H__
+
+ /*
+  * Convert a U6.4 fixed-point bits-per-pixel (bpp) value to an integer bpp value.
+  */
+static inline int intel_fractional_bpp_from_x16(int bpp_x16)
+{
+	return bpp_x16 >> 4;
+}
+
+/*
+ * Extract the fractional part of a U6.4 fixed-point bpp value based on the
+ * last 4 bits representing fractional bits, obtained by multiplying by 10000
+ * and then dividing by 16, as the bpp value is initially left-shifted by 4
+ * to allocate 4 bits for the fractional part.
+ */
+static inline int intel_fractional_bpp_decimal(int bpp_x16)
+{
+	return (bpp_x16 & 0xf) * 625;
+}
+
+/*
+ * Convert bits-per-pixel (bpp) to a U6.4 fixed-point representation.
+ */
+static inline int intel_fractional_bpp_to_x16(int bpp)
+{
+	return bpp << 4;
+}
+
+#endif /*  __INTEL_FRACTIONAL_HELPERS_H__ */
+
diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.c b/drivers/gpu/drm/i915/display/intel_vdsc.c
index 6757dbae9ee5..142c886f4776 100644
--- a/drivers/gpu/drm/i915/display/intel_vdsc.c
+++ b/drivers/gpu/drm/i915/display/intel_vdsc.c
@@ -15,6 +15,7 @@ 
 #include "intel_de.h"
 #include "intel_display_types.h"
 #include "intel_dsi.h"
+#include "intel_fractional_helper.h"
 #include "intel_qp_tables.h"
 #include "intel_vdsc.h"
 #include "intel_vdsc_regs.h"
@@ -248,7 +249,7 @@  int intel_dsc_compute_params(struct intel_crtc_state *pipe_config)
 	struct intel_crtc *crtc = to_intel_crtc(pipe_config->uapi.crtc);
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
 	struct drm_dsc_config *vdsc_cfg = &pipe_config->dsc.config;
-	u16 compressed_bpp = pipe_config->dsc.compressed_bpp;
+	u16 compressed_bpp = intel_fractional_bpp_from_x16(pipe_config->dsc.compressed_bpp_x16);
 	int err;
 	int ret;
 
@@ -874,7 +875,7 @@  static void intel_dsc_get_pps_config(struct intel_crtc_state *crtc_state)
 	if (vdsc_cfg->native_420)
 		vdsc_cfg->bits_per_pixel >>= 1;
 
-	crtc_state->dsc.compressed_bpp = vdsc_cfg->bits_per_pixel >> 4;
+	crtc_state->dsc.compressed_bpp_x16 = vdsc_cfg->bits_per_pixel;
 
 	/* PPS 2 */
 	pps_temp = intel_dsc_pps_read_and_verify(crtc_state, 2);