linux-kernel - Re: [PATCH v2] drm: bridge: fsl-ldb: fixup mode on freq mismatch

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Message-ID: <202412042024.4mJmO3sM-lkp@intel.com>
Date: Wed, 4 Dec 2024 20:48:23 +0800
From: kernel test robot <lkp@...el.com>
To: Nikolaus Voss <nv@...n.de>,
	Alexander Stein <alexander.stein@...tq-group.com>,
	Liu Ying <victor.liu@....com>,
	Luca Ceresoli <luca.ceresoli@...tlin.com>,
	Fabio Estevam <festevam@...x.de>, Marek Vasut <marex@...x.de>,
	Andrzej Hajda <andrzej.hajda@...el.com>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Robert Foss <rfoss@...nel.org>,
	Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
	Jonas Karlman <jonas@...boo.se>,
	Jernej Skrabec <jernej.skrabec@...il.com>,
	David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>,
	miquel.raynal@...tlin.com, nikolaus.voss@...g-streit.com
Cc: llvm@...ts.linux.dev, oe-kbuild-all@...ts.linux.dev,
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] drm: bridge: fsl-ldb: fixup mode on freq mismatch

Hi Nikolaus,

kernel test robot noticed the following build warnings:

[auto build test WARNING on linus/master]
[also build test WARNING on drm-intel/for-linux-next drm-intel/for-linux-next-fixes drm-tip/drm-tip v6.13-rc1 next-20241203]
[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/Nikolaus-Voss/drm-bridge-fsl-ldb-fixup-mode-on-freq-mismatch/20241204-115306
base:   linus/master
patch link:    https://lore.kernel.org/r/20241203191111.47B56F7%40mail.steuer-voss.de
patch subject: [PATCH v2] drm: bridge: fsl-ldb: fixup mode on freq mismatch
config: arm-randconfig-003-20241204 (https://download.01.org/0day-ci/archive/20241204/202412042024.4mJmO3sM-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241204/202412042024.4mJmO3sM-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@...el.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202412042024.4mJmO3sM-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/gpu/drm/bridge/fsl-ldb.c:125:30: warning: omitting the parameter name in a function definition is a C2x extension [-Wc2x-extensions]
                                   struct drm_bridge_state *,
                                                            ^
   drivers/gpu/drm/bridge/fsl-ldb.c:127:33: warning: omitting the parameter name in a function definition is a C2x extension [-Wc2x-extensions]
                                   struct drm_connector_state *)
                                                               ^
   2 warnings generated.


vim +125 drivers/gpu/drm/bridge/fsl-ldb.c

   123	
   124	static int fsl_ldb_atomic_check(struct drm_bridge *bridge,
 > 125					struct drm_bridge_state *,
   126					struct drm_crtc_state *crtc_state,
   127					struct drm_connector_state *)
   128	{
   129		struct fsl_ldb *fsl_ldb = to_fsl_ldb(bridge);
   130		const struct drm_display_mode *mode = &crtc_state->mode;
   131		unsigned long requested_link_freq =
   132			fsl_ldb_link_frequency(fsl_ldb, mode->clock);
   133		unsigned long freq = clk_round_rate(fsl_ldb->clk, requested_link_freq);
   134	
   135		if (freq != requested_link_freq) {
   136			/*
   137			 * this will lead to flicker and incomplete lines on
   138			 * the attached display, adjust the CRTC clock
   139			 * accordingly.
   140			 */
   141			struct drm_display_mode *adjusted_mode = &crtc_state->adjusted_mode;
   142			int pclk = freq / fsl_ldb_link_frequency(fsl_ldb, 1);
   143	
   144			if (adjusted_mode->clock != pclk) {
   145				dev_warn(fsl_ldb->dev, "Adjusted pixel clk to match LDB clk (%d kHz -> %d kHz)!\n",
   146					 adjusted_mode->clock, pclk);
   147	
   148				adjusted_mode->clock = pclk;
   149				adjusted_mode->crtc_clock = pclk;
   150			}
   151		}
   152	
   153		return 0;
   154	}
   155	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki