Re: [PATCH v6 2/2] drm/bridge: Add NWL MIPI DSI host controller support (fwd)

From: Julia Lawall
Date: Sun Sep 22 2019 - 14:44:35 EST


Hello,

Color_format is unsigned, so it won't be less than 0 on line 272.

julia

---------- Forwarded message ----------
Date: Mon, 23 Sep 2019 02:29:34 +0800
From: kbuild test robot <lkp@xxxxxxxxx>
To: kbuild@xxxxxx
Cc: Julia Lawall <julia.lawall@xxxxxxx>
Subject: Re: [PATCH v6 2/2] drm/bridge: Add NWL MIPI DSI host controller support

CC: kbuild-all@xxxxxx
In-Reply-To: <c0ac0b203fb65ae7efd1b9b54664b491ca2fb157.1569170717.git.agx@xxxxxxxxxxx>
References: <c0ac0b203fb65ae7efd1b9b54664b491ca2fb157.1569170717.git.agx@xxxxxxxxxxx>
TO: "Guido Günther" <agx@xxxxxxxxxxx>
CC:

Hi "Guido,

I love your patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[cannot apply to v5.3 next-20190920]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url: https://github.com/0day-ci/linux/commits/Guido-G-nther/drm-bridge-Add-NWL-MIPI-DSI-host-controller-support/20190923-005010
:::::: branch date: 2 hours ago
:::::: commit date: 2 hours ago

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@xxxxxxxxx>
Reported-by: Julia Lawall <julia.lawall@xxxxxxx>

>> drivers/gpu/drm/bridge/nwl-dsi.c:272:5-17: WARNING: Unsigned expression compared with zero: color_format < 0

# https://github.com/0day-ci/linux/commit/060069512cb50e3218b55005b6cc92b82e0a7856
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout 060069512cb50e3218b55005b6cc92b82e0a7856
vim +272 drivers/gpu/drm/bridge/nwl-dsi.c

060069512cb50e Guido Günther 2019-09-22 245
060069512cb50e Guido Günther 2019-09-22 246 static int nwl_dsi_config_dpi(struct nwl_dsi *dsi)
060069512cb50e Guido Günther 2019-09-22 247 {
060069512cb50e Guido Günther 2019-09-22 248 u32 color_format, mode;
060069512cb50e Guido Günther 2019-09-22 249 bool burst_mode;
060069512cb50e Guido Günther 2019-09-22 250 int hfront_porch, hback_porch, vfront_porch, vback_porch;
060069512cb50e Guido Günther 2019-09-22 251 int hsync_len, vsync_len;
060069512cb50e Guido Günther 2019-09-22 252
060069512cb50e Guido Günther 2019-09-22 253 hfront_porch = dsi->mode.hsync_start - dsi->mode.hdisplay;
060069512cb50e Guido Günther 2019-09-22 254 hsync_len = dsi->mode.hsync_end - dsi->mode.hsync_start;
060069512cb50e Guido Günther 2019-09-22 255 hback_porch = dsi->mode.htotal - dsi->mode.hsync_end;
060069512cb50e Guido Günther 2019-09-22 256
060069512cb50e Guido Günther 2019-09-22 257 vfront_porch = dsi->mode.vsync_start - dsi->mode.vdisplay;
060069512cb50e Guido Günther 2019-09-22 258 vsync_len = dsi->mode.vsync_end - dsi->mode.vsync_start;
060069512cb50e Guido Günther 2019-09-22 259 vback_porch = dsi->mode.vtotal - dsi->mode.vsync_end;
060069512cb50e Guido Günther 2019-09-22 260
060069512cb50e Guido Günther 2019-09-22 261 DRM_DEV_DEBUG_DRIVER(dsi->dev, "hfront_porch = %d\n", hfront_porch);
060069512cb50e Guido Günther 2019-09-22 262 DRM_DEV_DEBUG_DRIVER(dsi->dev, "hback_porch = %d\n", hback_porch);
060069512cb50e Guido Günther 2019-09-22 263 DRM_DEV_DEBUG_DRIVER(dsi->dev, "hsync_len = %d\n", hsync_len);
060069512cb50e Guido Günther 2019-09-22 264 DRM_DEV_DEBUG_DRIVER(dsi->dev, "hdisplay = %d\n", dsi->mode.hdisplay);
060069512cb50e Guido Günther 2019-09-22 265 DRM_DEV_DEBUG_DRIVER(dsi->dev, "vfront_porch = %d\n", vfront_porch);
060069512cb50e Guido Günther 2019-09-22 266 DRM_DEV_DEBUG_DRIVER(dsi->dev, "vback_porch = %d\n", vback_porch);
060069512cb50e Guido Günther 2019-09-22 267 DRM_DEV_DEBUG_DRIVER(dsi->dev, "vsync_len = %d\n", vsync_len);
060069512cb50e Guido Günther 2019-09-22 268 DRM_DEV_DEBUG_DRIVER(dsi->dev, "vactive = %d\n", dsi->mode.vdisplay);
060069512cb50e Guido Günther 2019-09-22 269 DRM_DEV_DEBUG_DRIVER(dsi->dev, "clock = %d kHz\n", dsi->mode.clock);
060069512cb50e Guido Günther 2019-09-22 270
060069512cb50e Guido Günther 2019-09-22 271 color_format = nwl_dsi_get_dpi_pixel_format(dsi->format);
060069512cb50e Guido Günther 2019-09-22 @272 if (color_format < 0) {
060069512cb50e Guido Günther 2019-09-22 273 DRM_DEV_ERROR(dsi->dev, "Invalid color format 0x%x\n",
060069512cb50e Guido Günther 2019-09-22 274 dsi->format);
060069512cb50e Guido Günther 2019-09-22 275 return color_format;
060069512cb50e Guido Günther 2019-09-22 276 }
060069512cb50e Guido Günther 2019-09-22 277 DRM_DEV_DEBUG_DRIVER(dsi->dev, "pixel fmt = %d\n", dsi->format);
060069512cb50e Guido Günther 2019-09-22 278
060069512cb50e Guido Günther 2019-09-22 279 nwl_dsi_write(dsi, NWL_DSI_INTERFACE_COLOR_CODING, NWL_DSI_DPI_24_BIT);
060069512cb50e Guido Günther 2019-09-22 280 nwl_dsi_write(dsi, NWL_DSI_PIXEL_FORMAT, color_format);
060069512cb50e Guido Günther 2019-09-22 281 /*
060069512cb50e Guido Günther 2019-09-22 282 * Adjusting input polarity based on the video mode results in
060069512cb50e Guido Günther 2019-09-22 283 * a black screen so always pick active low:
060069512cb50e Guido Günther 2019-09-22 284 */
060069512cb50e Guido Günther 2019-09-22 285 nwl_dsi_write(dsi, NWL_DSI_VSYNC_POLARITY,
060069512cb50e Guido Günther 2019-09-22 286 NWL_DSI_VSYNC_POLARITY_ACTIVE_LOW);
060069512cb50e Guido Günther 2019-09-22 287 nwl_dsi_write(dsi, NWL_DSI_HSYNC_POLARITY,
060069512cb50e Guido Günther 2019-09-22 288 NWL_DSI_HSYNC_POLARITY_ACTIVE_LOW);
060069512cb50e Guido Günther 2019-09-22 289
060069512cb50e Guido Günther 2019-09-22 290 burst_mode = (dsi->dsi_mode_flags & MIPI_DSI_MODE_VIDEO_BURST) &&
060069512cb50e Guido Günther 2019-09-22 291 !(dsi->dsi_mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE);
060069512cb50e Guido Günther 2019-09-22 292
060069512cb50e Guido Günther 2019-09-22 293 if (burst_mode) {
060069512cb50e Guido Günther 2019-09-22 294 nwl_dsi_write(dsi, NWL_DSI_VIDEO_MODE, NWL_DSI_VM_BURST_MODE);
060069512cb50e Guido Günther 2019-09-22 295 nwl_dsi_write(dsi, NWL_DSI_PIXEL_FIFO_SEND_LEVEL, 256);
060069512cb50e Guido Günther 2019-09-22 296 } else {
060069512cb50e Guido Günther 2019-09-22 297 mode = ((dsi->dsi_mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE) ?
060069512cb50e Guido Günther 2019-09-22 298 NWL_DSI_VM_BURST_MODE_WITH_SYNC_PULSES :
060069512cb50e Guido Günther 2019-09-22 299 NWL_DSI_VM_NON_BURST_MODE_WITH_SYNC_EVENTS);
060069512cb50e Guido Günther 2019-09-22 300 nwl_dsi_write(dsi, NWL_DSI_VIDEO_MODE, mode);
060069512cb50e Guido Günther 2019-09-22 301 nwl_dsi_write(dsi, NWL_DSI_PIXEL_FIFO_SEND_LEVEL,
060069512cb50e Guido Günther 2019-09-22 302 dsi->mode.hdisplay);
060069512cb50e Guido Günther 2019-09-22 303 }
060069512cb50e Guido Günther 2019-09-22 304
060069512cb50e Guido Günther 2019-09-22 305 nwl_dsi_write(dsi, NWL_DSI_HFP, hfront_porch);
060069512cb50e Guido Günther 2019-09-22 306 nwl_dsi_write(dsi, NWL_DSI_HBP, hback_porch);
060069512cb50e Guido Günther 2019-09-22 307 nwl_dsi_write(dsi, NWL_DSI_HSA, hsync_len);
060069512cb50e Guido Günther 2019-09-22 308
060069512cb50e Guido Günther 2019-09-22 309 nwl_dsi_write(dsi, NWL_DSI_ENABLE_MULT_PKTS, 0x0);
060069512cb50e Guido Günther 2019-09-22 310 nwl_dsi_write(dsi, NWL_DSI_BLLP_MODE, 0x1);
060069512cb50e Guido Günther 2019-09-22 311 nwl_dsi_write(dsi, NWL_DSI_USE_NULL_PKT_BLLP, 0x0);
060069512cb50e Guido Günther 2019-09-22 312 nwl_dsi_write(dsi, NWL_DSI_VC, 0x0);
060069512cb50e Guido Günther 2019-09-22 313
060069512cb50e Guido Günther 2019-09-22 314 nwl_dsi_write(dsi, NWL_DSI_PIXEL_PAYLOAD_SIZE, dsi->mode.hdisplay);
060069512cb50e Guido Günther 2019-09-22 315 nwl_dsi_write(dsi, NWL_DSI_VACTIVE, dsi->mode.vdisplay - 1);
060069512cb50e Guido Günther 2019-09-22 316 nwl_dsi_write(dsi, NWL_DSI_VBP, vback_porch);
060069512cb50e Guido Günther 2019-09-22 317 nwl_dsi_write(dsi, NWL_DSI_VFP, vfront_porch);
060069512cb50e Guido Günther 2019-09-22 318
060069512cb50e Guido Günther 2019-09-22 319 return 0;
060069512cb50e Guido Günther 2019-09-22 320 }
060069512cb50e Guido Günther 2019-09-22 321

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