[PATCH 6/9] drm/i915/display: Add DSC pixel replication

[kernel test robot]

Hi Ankit,

kernel test robot noticed the following build warnings:

[auto build test WARNING on drm-intel/for-linux-next]
[also build test WARNING on next-20241015]
[cannot apply to drm-intel/for-linux-next-fixes drm-tip/drm-tip linus/master v6.12-rc3]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Ankit-Nautiyal/drm-i915-display-Prepare-for-dsc-3-stream-splitter/20241014-161007
base:   git://anongit.freedesktop.org/drm-intel for-linux-next
patch link:    https://lore.kernel.org/r/20241014081000.2844245-7-ankit.k.nautiyal%40intel.com
patch subject: [PATCH 6/9] drm/i915/display: Add DSC pixel replication
config: i386-defconfig (https://download.01.org/0day-ci/archive/20241016/202410160018.hjWyI23D-lkp@intel.com/config)
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241016/202410160018.hjWyI23D-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 at intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410160018.hjWyI23D-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/gpu/drm/i915/display/intel_vdsc.c:1022:6: warning: variable 'dss_ctl3' is uninitialized when used here [-Wuninitialized]
    1022 |         if (dss_ctl3 & DSC_PIXEL_REPLICATION_MASK)
         |             ^~~~~~~~
   drivers/gpu/drm/i915/display/intel_vdsc.c:991:34: note: initialize the variable 'dss_ctl3' to silence this warning
     991 |         u32 dss_ctl1, dss_ctl2, dss_ctl3;
         |                                         ^
         |                                          = 0
   1 warning generated.


vim +/dss_ctl3 +1022 drivers/gpu/drm/i915/display/intel_vdsc.c

   983	
   984	void intel_dsc_get_config(struct intel_crtc_state *crtc_state)
   985	{
   986		struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
   987		struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
   988		enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
   989		enum intel_display_power_domain power_domain;
   990		intel_wakeref_t wakeref;
   991		u32 dss_ctl1, dss_ctl2, dss_ctl3;
   992	
   993		if (!intel_dsc_source_support(crtc_state))
   994			return;
   995	
   996		power_domain = intel_dsc_power_domain(crtc, cpu_transcoder);
   997	
   998		wakeref = intel_display_power_get_if_enabled(dev_priv, power_domain);
   999		if (!wakeref)
  1000			return;
  1001	
  1002		dss_ctl1 = intel_de_read(dev_priv, dss_ctl1_reg(crtc, cpu_transcoder));
  1003		dss_ctl2 = intel_de_read(dev_priv, dss_ctl2_reg(crtc, cpu_transcoder));
  1004	
  1005		if (IS_BATTLEMAGE(dev_priv))
  1006			dss_ctl3 = intel_de_read(dev_priv, BMG_PIPE_DSS_CTL3(crtc_state->cpu_transcoder));
  1007	
  1008		crtc_state->dsc.compression_enable = dss_ctl2 & VDSC0_ENABLE;
  1009		if (!crtc_state->dsc.compression_enable)
  1010			goto out;
  1011	
  1012		if (dss_ctl1 & JOINER_ENABLE) {
  1013			if (dss_ctl2 & (VDSC2_ENABLE | SMALL_JOINER_CONFIG_3_ENGINES))
  1014				crtc_state->dsc.dsc_split = INTEL_DSC_SPLIT_3_STREAMS;
  1015	
  1016			else if (dss_ctl2 & VDSC1_ENABLE)
  1017				crtc_state->dsc.dsc_split = INTEL_DSC_SPLIT_2_STREAMS;
  1018		} else {
  1019			crtc_state->dsc.dsc_split = INTEL_DSC_SPLIT_DISABLED;
  1020		}
  1021	
> 1022		if (dss_ctl3 & DSC_PIXEL_REPLICATION_MASK)
  1023			crtc_state->dsc.pixel_replication_count =
  1024				dss_ctl3 & DSC_PIXEL_REPLICATION_MASK;
  1025	
  1026		intel_dsc_get_pps_config(crtc_state);
  1027	out:
  1028		intel_display_power_put(dev_priv, power_domain, wakeref);
  1029	}
  1030	

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