Hi Dan Carpenter,
Thanks for the feedback.
> Subject: [bug report] drm: rcar-du: Add RZ/G2L DSI driver
>
> Hello Biju Das,
>
> The patch 7a043f978ed1: "drm: rcar-du: Add RZ/G2L DSI driver" from Sep
> 20, 2022, leads to the following Smatch static checker warning:
>
> drivers/gpu/drm/rcar-du/rzg2l_mipi_dsi.c:372
> rzg2l_mipi_dsi_set_display_timing()
> warn: uninitialized special assign 'vich1ppsetr |= (1 << 15)'
>
> drivers/gpu/drm/rcar-du/rzg2l_mipi_dsi.c
> 347 static void rzg2l_mipi_dsi_set_display_timing(struct
> rzg2l_mipi_dsi *dsi,
> 348 const struct
> drm_display_mode *mode)
> 349 {
> 350 u32 vich1ppsetr;
> 351 u32 vich1vssetr;
> 352 u32 vich1vpsetr;
> 353 u32 vich1hssetr;
> 354 u32 vich1hpsetr;
> 355 int dsi_format;
> 356 u32 delay[2];
> 357 u8 index;
> 358
> 359 /* Configuration for Pixel Packet */
> 360 dsi_format = mipi_dsi_pixel_format_to_bpp(dsi->format);
> 361 switch (dsi_format) {
> 362 case 24:
> 363 vich1ppsetr = VICH1PPSETR_DT_RGB24;
> 364 break;
> 365 case 18:
> 366 vich1ppsetr = VICH1PPSETR_DT_RGB18;
> 367 break;
>
> What if mipi_dsi_pixel_format_to_bpp() returns 16?
This condition is already validated in rzg2l_mipi_dsi_host_attach(). For val of 16,
It returns error. See line 623.
default:
dev_err(dsi->dev, "Unsupported format 0x%04x\n", device->format);
return -EINVAL;
Cheers,
Biju
>
> 368 }
> 369
> 370 if ((dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
> &&
> 371 !(dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST))
> --> 372 vich1ppsetr |= VICH1PPSETR_TXESYNC_PULSE;
> ^^^^^^^^^^^
> Uninitialized.
>
> 373
> 374 rzg2l_mipi_dsi_link_write(dsi, VICH1PPSETR,
> vich1ppsetr);
>
> regards,
> dan carpenter
