drm/mediatek: Add missing IS_ERR check for ovl_adaptor platform devicegrafted

platform_device_register_data() can fail and return an ERR_PTR, but the
return value is used without checking, leading to an invalid pointer
being stored in ddp_comp[].dev and passed to component_match_add() and
mtk_ddp_comp_init(), which could result in a kernel crash.

Add an IS_ERR() check to jump to the error handling path on failure.

Fixes: 0d9eee9118b7 ("drm/mediatek: Add drm ovl_adaptor sub driver for MT8195")
Cc: stable@vger.kernel.org
Signed-off-by: Haojie Li <lihaojie@kylinos.cn>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20260825100845.438893-1-lihaojie@kylinos.cn/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

1 files changed, 71 insertions, 0 deletions

diff --git a/Documentation/fb/efifb.rst b/Documentation/fb/efifb.rst
new file mode 100644
index 000000000..3d4aab406
--- /dev/null
+++ b/Documentation/fb/efifb.rst
@@ -0,0 +1,71 @@
+===================================
+efifb - Generic EFI platform driver
+===================================
+
+This is a generic EFI platform driver for systems with UEFI firmware. The
+system must be booted via the EFI stub for this to be usable. efifb supports
+both firmware with Graphics Output Protocol (GOP) displays as well as older
+systems with only Universal Graphics Adapter (UGA) displays.
+
+Supported Hardware
+==================
+
+- iMac 17"/20"
+- Macbook
+- Macbook Pro 15"/17"
+- MacMini
+- ARM/ARM64/X86 systems with UEFI firmware
+
+How to use it?
+==============
+
+For UGA displays, efifb does not have any kind of autodetection of your
+machine.
+
+You have to add the following kernel parameters in your elilo.conf::
+
+	Macbook :
+		video=efifb:macbook
+	MacMini :
+		video=efifb:mini
+	Macbook Pro 15", iMac 17" :
+		video=efifb:i17
+	Macbook Pro 17", iMac 20" :
+		video=efifb:i20
+
+For GOP displays, efifb can autodetect the display's resolution and framebuffer
+address, so these should work out of the box without any special parameters.
+
+Accepted options:
+
+======= ===========================================================
+nowc	Don't map the framebuffer write combined. This can be used
+	to workaround side-effects and slowdowns on other CPU cores
+	when large amounts of console data are written.
+======= ===========================================================
+
+Options for GOP displays:
+
+mode=n
+        The EFI stub will set the mode of the display to mode number n if
+        possible.
+
+<xres>x<yres>[-(rgb|bgr|<bpp>)]
+        The EFI stub will search for a display mode that matches the specified
+        horizontal and vertical resolution, and optionally bit depth, and set
+        the mode of the display to it if one is found. The bit depth can either
+        "rgb" or "bgr" to match specifically those pixel formats, or a number
+        for a mode with matching bits per pixel.
+
+auto
+        The EFI stub will choose the mode with the highest resolution (product
+        of horizontal and vertical resolution). If there are multiple modes
+        with the highest resolution, it will choose one with the highest color
+        depth.
+
+list
+        The EFI stub will list out all the display modes that are available. A
+        specific mode can then be chosen using one of the above options for the
+        next boot.
+
+Edgar Hucek <gimli@dark-green.com>