[PATCH] drm/vkms: add module parameter to set background color

[Dan Carpenter]

Hi Maíra,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Ma-ra-Canal/drm-vkms-add-module-parameter-to-set-background-color/20230407-012233
base:   git://anongit.freedesktop.org/drm/drm-misc drm-misc-next
patch link:    https://lore.kernel.org/r/20230406172002.124456-1-mcanal%40igalia.com
patch subject: [PATCH] drm/vkms: add module parameter to set background color
config: i386-randconfig-m031-20230403 (https://download.01.org/0day-ci/archive/20230408/202304082018.PXAwWhse-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-8) 11.3.0

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp at intel.com>
| Reported-by: Dan Carpenter <error27 at gmail.com>
| Link: https://lore.kernel.org/r/202304082018.PXAwWhse-lkp@intel.com/

smatch warnings:
drivers/gpu/drm/vkms/vkms_composer.c:93 blend() warn: right shifting more than type allows 32 vs 32

vim +93 drivers/gpu/drm/vkms/vkms_composer.c

d725068207852d drivers/gpu/drm/vkms/vkms_composer.c Maíra Canal     2023-04-06   82  static void blend(struct vkms_device *vkms_dev,
d725068207852d drivers/gpu/drm/vkms/vkms_composer.c Maíra Canal     2023-04-06   83  		  struct vkms_writeback_job *wb,
8ba1648567e289 drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05   84  		  struct vkms_crtc_state *crtc_state,
8ba1648567e289 drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05   85  		  u32 *crc32, struct line_buffer *stage_buffer,
8ba1648567e289 drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05   86  		  struct line_buffer *output_buffer, size_t row_size)
39cba5cf8c2c23 drivers/gpu/drm/vkms/vkms_composer.c Melissa Wen     2020-08-25   87  {
8ba1648567e289 drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05   88  	struct vkms_plane_state **plane = crtc_state->active_planes;
8ba1648567e289 drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05   89  	u32 n_active_planes = crtc_state->num_active_planes;
39cba5cf8c2c23 drivers/gpu/drm/vkms/vkms_composer.c Melissa Wen     2020-08-25   90  
d725068207852d drivers/gpu/drm/vkms/vkms_composer.c Maíra Canal     2023-04-06   91  	const struct pixel_argb_u16 background_color = {
d725068207852d drivers/gpu/drm/vkms/vkms_composer.c Maíra Canal     2023-04-06   92  		.a =  0xffff,
d725068207852d drivers/gpu/drm/vkms/vkms_composer.c Maíra Canal     2023-04-06  @93  		.r = (*vkms_dev->config->background_color >> 32) & 0xffff,
                                                                                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This shift always results in zero.

d725068207852d drivers/gpu/drm/vkms/vkms_composer.c Maíra Canal     2023-04-06   94  		.g = (*vkms_dev->config->background_color >> 16) & 0xffff,
d725068207852d drivers/gpu/drm/vkms/vkms_composer.c Maíra Canal     2023-04-06   95  		.b = *vkms_dev->config->background_color & 0xffff,
d725068207852d drivers/gpu/drm/vkms/vkms_composer.c Maíra Canal     2023-04-06   96  	};
32a1648aca4409 drivers/gpu/drm/vkms/vkms_composer.c Melissa Wen     2021-04-24   97  
bc0d7fdefec62e drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05   98  	size_t crtc_y_limit = crtc_state->base.crtc->mode.vdisplay;
39cba5cf8c2c23 drivers/gpu/drm/vkms/vkms_composer.c Melissa Wen     2020-08-25   99  
bc0d7fdefec62e drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05  100  	for (size_t y = 0; y < crtc_y_limit; y++) {
bc0d7fdefec62e drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05  101  		fill_background(&background_color, output_buffer);
bc0d7fdefec62e drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05  102  
bc0d7fdefec62e drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05  103  		/* The active planes are composed associatively in z-order. */
bc0d7fdefec62e drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05  104  		for (size_t i = 0; i < n_active_planes; i++) {
8ba1648567e289 drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05  105  			if (!check_y_limit(plane[i]->frame_info, y))
8ba1648567e289 drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05  106  				continue;
8ba1648567e289 drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05  107  
8ba1648567e289 drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05  108  			plane[i]->plane_read(stage_buffer, plane[i]->frame_info, y);
8ba1648567e289 drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05  109  			pre_mul_alpha_blend(plane[i]->frame_info, stage_buffer,
8ba1648567e289 drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05  110  					    output_buffer);
db7f419c06d7cc drivers/gpu/drm/vkms/vkms_crc.c      Haneen Mohammed 2018-09-06  111  		}
8ba1648567e289 drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05  112  
8ba1648567e289 drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05  113  		*crc32 = crc32_le(*crc32, (void *)output_buffer->pixels, row_size);
8ba1648567e289 drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05  114  
8ba1648567e289 drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05  115  		if (wb)
8ba1648567e289 drivers/gpu/drm/vkms/vkms_composer.c Igor Torrente   2022-09-05  116  			wb->wb_write(&wb->wb_frame_info, output_buffer, y);
db7f419c06d7cc drivers/gpu/drm/vkms/vkms_crc.c      Haneen Mohammed 2018-09-06  117  	}
db7f419c06d7cc drivers/gpu/drm/vkms/vkms_crc.c      Haneen Mohammed 2018-09-06  118  }

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