From bca94cc345633e29ad61a7f1ade0bd035bd7d1f7 Mon Sep 17 00:00:00 2001 From: Fabio Estevam Date: Mon, 19 May 2025 13:32:30 -0300 Subject: [PATCH] drm/tiny: panel-mipi-dbi: Use drm_client_setup_with_fourcc() commit 9c1798259b9420f38f1fa1b83e3d864c3eb1a83e upstream. Since commit 559358282e5b ("drm/fb-helper: Don't use the preferred depth for the BPP default"), RGB565 displays such as the CFAF240320X no longer render correctly: colors are distorted and the content is shown twice horizontally. This regression is due to the fbdev emulation layer defaulting to 32 bits per pixel, whereas the display expects 16 bpp (RGB565). As a result, the framebuffer data is incorrectly interpreted by the panel. Fix the issue by calling drm_client_setup_with_fourcc() with a format explicitly selected based on the display's bits-per-pixel value. For 16 bpp, use DRM_FORMAT_RGB565; for other values, fall back to the previous behavior. This ensures that the allocated framebuffer format matches the hardware expectations, avoiding color and layout corruption. Tested on a CFAF240320X display with an RGB565 configuration, confirming correct colors and layout after applying this patch. Cc: stable@vger.kernel.org Fixes: 559358282e5b ("drm/fb-helper: Don't use the preferred depth for the BPP default") Signed-off-by: Fabio Estevam Reviewed-by: Thomas Zimmermann Reviewed-by: Javier Martinez Canillas Signed-off-by: Thomas Zimmermann Link: https://lore.kernel.org/r/20250417103458.2496790-1-festevam@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/tiny/panel-mipi-dbi.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/tiny/panel-mipi-dbi.c b/drivers/gpu/drm/tiny/panel-mipi-dbi.c index e66729b31bd6..ac159e8127d5 100644 --- a/drivers/gpu/drm/tiny/panel-mipi-dbi.c +++ b/drivers/gpu/drm/tiny/panel-mipi-dbi.c @@ -390,7 +390,10 @@ static int panel_mipi_dbi_spi_probe(struct spi_device *spi) spi_set_drvdata(spi, drm); - drm_client_setup(drm, NULL); + if (bpp == 16) + drm_client_setup_with_fourcc(drm, DRM_FORMAT_RGB565); + else + drm_client_setup_with_fourcc(drm, DRM_FORMAT_RGB888); return 0; }