From 9d4c98219598e77ca7044c453ae6994519ac0a96 Mon Sep 17 00:00:00 2001 From: Roshan Kumar Date: Fri, 11 Sep 2026 00:55:26 +0530 Subject: [PATCH] drm/pl111: drop alpha formats the hardware cannot scan out The PL110/PL111 controller scans out a single framebuffer and never blends its alpha channel with anything. In every pixel-format table each alpha-carrying entry (ARGB/ABGR in 8888, 1555 and 4444) maps to exactly the same register configuration as its XRGB/XBGR counterpart, so the alpha byte was never used by the hardware. Commit 860e748bddcc ("drm: ensure blend mode supported if pixel format with alpha exposed") added validation that warns when a plane exposes alpha formats without a pixel blend mode property, and PL111 does exactly that. With panic_on_warn enabled the warning prevents the syzkaller vexpress-a15 manager from booting. Drivers should not report formats they do not support, so remove the alpha formats from all variant tables: the generic PL110, PL111 and Nomadik tables in pl111_drv.c and the board-specific Integrator, IM-PD1, Versatile and RealView/Versatile-Express tables in pl111_versatile.c, plus the now dead case labels in the display setup and the Versatile syscon connector switch, instead of advertising a blend mode property. Behavior is unchanged for userspace that picks an XRGB/XBGR/RGB format; alpha-picking clients fall back to the identical X variant. Link: https://github.com/google/syzkaller/issues/7805 Fixes: 860e748bddcc ("drm: ensure blend mode supported if pixel format with alpha exposed") Signed-off-by: Roshan Kumar Changes in v2: drop the alpha formats entirely instead of advertising a DRM_MODE_BLEND_PIXEL_NONE property, per review feedback from Thomas Zimmermann. Leandro's Reviewed-by from v1 is not carried as the approach changed. Changes in v3: v2 missed the board-specific variant tables in pl111_versatile.c (Integrator, IM-PD1, Versatile, RealView and Versatile Express), which still exposed alpha formats and would fall through to the WARN_ONCE default in pl111_display_enable() on those boards. Pointed out by the sashiko AI reviewer. Reviewed-by: Thomas Zimmermann Link: https://github.com/google/syzkaller/issues/7805 Signed-off-by: Linus Walleij Link: https://patch.msgid.link/20260910192526.137057-1-roshaen09@gmail.com --- drivers/gpu/drm/pl111/pl111_display.c | 6 ------ drivers/gpu/drm/pl111/pl111_drv.c | 16 ---------------- drivers/gpu/drm/pl111/pl111_versatile.c | 18 ------------------ 3 files changed, 40 deletions(-) diff --git a/drivers/gpu/drm/pl111/pl111_display.c b/drivers/gpu/drm/pl111/pl111_display.c index 5d10bc5fdf1f..e1b513d36c27 100644 --- a/drivers/gpu/drm/pl111/pl111_display.c +++ b/drivers/gpu/drm/pl111/pl111_display.c @@ -267,14 +267,12 @@ static void pl111_display_enable(struct drm_simple_display_pipe *pipe, if (priv->variant->st_bitmux_control) cntl |= CNTL_ST_LCDBPP24_PACKED; break; - case DRM_FORMAT_ABGR8888: case DRM_FORMAT_XBGR8888: if (priv->variant->st_bitmux_control) cntl |= CNTL_LCDBPP24 | CNTL_BGR; else cntl |= CNTL_LCDBPP24; break; - case DRM_FORMAT_ARGB8888: case DRM_FORMAT_XRGB8888: if (priv->variant->st_bitmux_control) cntl |= CNTL_LCDBPP24; @@ -297,13 +295,11 @@ static void pl111_display_enable(struct drm_simple_display_pipe *pipe, else cntl |= CNTL_LCDBPP16_565 | CNTL_BGR; break; - case DRM_FORMAT_ABGR1555: case DRM_FORMAT_XBGR1555: cntl |= CNTL_LCDBPP16; if (priv->variant->st_bitmux_control) cntl |= CNTL_ST_1XBPP_5551 | CNTL_BGR; break; - case DRM_FORMAT_ARGB1555: case DRM_FORMAT_XRGB1555: cntl |= CNTL_LCDBPP16; if (priv->variant->st_bitmux_control) @@ -311,13 +307,11 @@ static void pl111_display_enable(struct drm_simple_display_pipe *pipe, else cntl |= CNTL_BGR; break; - case DRM_FORMAT_ABGR4444: case DRM_FORMAT_XBGR4444: cntl |= CNTL_LCDBPP16_444; if (priv->variant->st_bitmux_control) cntl |= CNTL_ST_1XBPP_444 | CNTL_BGR; break; - case DRM_FORMAT_ARGB4444: case DRM_FORMAT_XRGB4444: cntl |= CNTL_LCDBPP16_444; if (priv->variant->st_bitmux_control) diff --git a/drivers/gpu/drm/pl111/pl111_drv.c b/drivers/gpu/drm/pl111/pl111_drv.c index 8ec659b3c08e..0e97261e988d 100644 --- a/drivers/gpu/drm/pl111/pl111_drv.c +++ b/drivers/gpu/drm/pl111/pl111_drv.c @@ -342,13 +342,9 @@ static void pl111_amba_shutdown(struct amba_device *amba_dev) * This early variant lacks the 565 and 444 pixel formats. */ static const u32 pl110_pixel_formats[] = { - DRM_FORMAT_ABGR8888, DRM_FORMAT_XBGR8888, - DRM_FORMAT_ARGB8888, DRM_FORMAT_XRGB8888, - DRM_FORMAT_ABGR1555, DRM_FORMAT_XBGR1555, - DRM_FORMAT_ARGB1555, DRM_FORMAT_XRGB1555, }; @@ -362,19 +358,13 @@ static const struct pl111_variant_data pl110_variant = { /* RealView, Versatile Express etc use this modern variant */ static const u32 pl111_pixel_formats[] = { - DRM_FORMAT_ABGR8888, DRM_FORMAT_XBGR8888, - DRM_FORMAT_ARGB8888, DRM_FORMAT_XRGB8888, DRM_FORMAT_BGR565, DRM_FORMAT_RGB565, - DRM_FORMAT_ABGR1555, DRM_FORMAT_XBGR1555, - DRM_FORMAT_ARGB1555, DRM_FORMAT_XRGB1555, - DRM_FORMAT_ABGR4444, DRM_FORMAT_XBGR4444, - DRM_FORMAT_ARGB4444, DRM_FORMAT_XRGB4444, }; @@ -388,19 +378,13 @@ static const struct pl111_variant_data pl111_variant = { static const u32 pl110_nomadik_pixel_formats[] = { DRM_FORMAT_RGB888, DRM_FORMAT_BGR888, - DRM_FORMAT_ABGR8888, DRM_FORMAT_XBGR8888, - DRM_FORMAT_ARGB8888, DRM_FORMAT_XRGB8888, DRM_FORMAT_BGR565, DRM_FORMAT_RGB565, - DRM_FORMAT_ABGR1555, DRM_FORMAT_XBGR1555, - DRM_FORMAT_ARGB1555, DRM_FORMAT_XRGB1555, - DRM_FORMAT_ABGR4444, DRM_FORMAT_XBGR4444, - DRM_FORMAT_ARGB4444, DRM_FORMAT_XRGB4444, }; diff --git a/drivers/gpu/drm/pl111/pl111_versatile.c b/drivers/gpu/drm/pl111/pl111_versatile.c index 0d8331a3909f..9a60f10231b1 100644 --- a/drivers/gpu/drm/pl111/pl111_versatile.c +++ b/drivers/gpu/drm/pl111/pl111_versatile.c @@ -209,9 +209,7 @@ static void pl111_versatile_enable(struct drm_device *drm, u32 format) drm_info(drm, "enable Versatile CLCD connectors\n"); switch (format) { - case DRM_FORMAT_ABGR8888: case DRM_FORMAT_XBGR8888: - case DRM_FORMAT_ARGB8888: case DRM_FORMAT_XRGB8888: val |= SYS_CLCD_MODE_888; break; @@ -221,9 +219,7 @@ static void pl111_versatile_enable(struct drm_device *drm, u32 format) case DRM_FORMAT_RGB565: val |= SYS_CLCD_MODE_565_B_LSB; break; - case DRM_FORMAT_ABGR1555: case DRM_FORMAT_XBGR1555: - case DRM_FORMAT_ARGB1555: case DRM_FORMAT_XRGB1555: val |= SYS_CLCD_MODE_5551; break; @@ -266,44 +262,30 @@ static void pl111_realview_clcd_enable(struct drm_device *drm, u32 format) /* PL110 pixel formats for Integrator, vanilla PL110 */ static const u32 pl110_integrator_pixel_formats[] = { - DRM_FORMAT_ABGR8888, DRM_FORMAT_XBGR8888, - DRM_FORMAT_ARGB8888, DRM_FORMAT_XRGB8888, - DRM_FORMAT_ABGR1555, DRM_FORMAT_XBGR1555, - DRM_FORMAT_ARGB1555, DRM_FORMAT_XRGB1555, }; /* Extended PL110 pixel formats for Integrator and Versatile */ static const u32 pl110_versatile_pixel_formats[] = { - DRM_FORMAT_ABGR8888, DRM_FORMAT_XBGR8888, - DRM_FORMAT_ARGB8888, DRM_FORMAT_XRGB8888, DRM_FORMAT_BGR565, /* Uses external PLD */ DRM_FORMAT_RGB565, /* Uses external PLD */ - DRM_FORMAT_ABGR1555, DRM_FORMAT_XBGR1555, - DRM_FORMAT_ARGB1555, DRM_FORMAT_XRGB1555, }; static const u32 pl111_realview_pixel_formats[] = { - DRM_FORMAT_ABGR8888, DRM_FORMAT_XBGR8888, - DRM_FORMAT_ARGB8888, DRM_FORMAT_XRGB8888, DRM_FORMAT_BGR565, DRM_FORMAT_RGB565, - DRM_FORMAT_ABGR1555, DRM_FORMAT_XBGR1555, - DRM_FORMAT_ARGB1555, DRM_FORMAT_XRGB1555, - DRM_FORMAT_ABGR4444, DRM_FORMAT_XBGR4444, - DRM_FORMAT_ARGB4444, DRM_FORMAT_XRGB4444, };