Merge tag 'drm-misc-next-2023-01-12' of git://anongit.freedesktop.org/drm/drm-misc into drm-next

drm-misc-next for v6.3:

UAPI Changes:

 * fourcc: Document Open Source user waiver

Cross-subsystem Changes:

 * firmware: fix color-format selection for system framebuffers

Core Changes:

 * format-helper: Add conversion from XRGB8888 to various sysfb formats;
   Make XRGB8888 the only driver-emulated legacy format

 * fb-helper: Avoid blank consoles from selecting an incorrect color format

 * probe-helper: Enable/disable HPD on connectors plus driver updates

 * Use drm_dbg_ helpers in several places

 * docs: Document defaults for CRTC backgrounds; Document use of drm_minor

Driver Changes:

 * arm/hdlcd: Use new debugfs helpers

 * gud: Use new debugfs helpers

 * panel: Support Visionox VTDR6130 AMOLED DSI; Support Himax HX8394; Convert
   many drivers to common generic DSI write-sequence helper

 * v3d: Do not opencode drm_gem_object_lookup()

 * vc4: Various HVS an CRTC fixes

 * vkms: Fix SEGFAULT from incorrect GEM-buffer mapping

 * Convert various drivers to i2c probe_new()

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/Y8ADeSzZDj+tpibF@linux-uq9g

1 files changed, 37 insertions, 6 deletions

diff --git a/drivers/firmware/sysfb_simplefb.c b/drivers/firmware/sysfb_simplefb.c
index a353e27f83f5..ce9c007ed66f 100644
--- a/drivers/firmware/sysfb_simplefb.c
+++ b/drivers/firmware/sysfb_simplefb.c
@@ -27,25 +27,56 @@ static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;
 __init bool sysfb_parse_mode(const struct screen_info *si,
 			     struct simplefb_platform_data *mode)
 {
-	const struct simplefb_format *f;
 	__u8 type;
+	u32 bits_per_pixel;
 	unsigned int i;
 
 	type = si->orig_video_isVGA;
 	if (type != VIDEO_TYPE_VLFB && type != VIDEO_TYPE_EFI)
 		return false;
 
+	/*
+	 * The meaning of depth and bpp for direct-color formats is
+	 * inconsistent:
+	 *
+	 *  - DRM format info specifies depth as the number of color
+	 *    bits; including alpha, but not including filler bits.
+	 *  - Linux' EFI platform code computes lfb_depth from the
+	 *    individual color channels, including the reserved bits.
+	 *  - VBE 1.1 defines lfb_depth for XRGB1555 as 16, but later
+	 *    versions use 15.
+	 *  - On the kernel command line, 'bpp' of 32 is usually
+	 *    XRGB8888 including the filler bits, but 15 is XRGB1555
+	 *    not including the filler bit.
+	 *
+	 * It's not easily possible to fix this in struct screen_info,
+	 * as this could break UAPI. The best solution is to compute
+	 * bits_per_pixel here and ignore lfb_depth. In the loop below,
+	 * ignore simplefb formats with alpha bits, as EFI and VESA
+	 * don't specify alpha channels.
+	 */
+	if (si->lfb_depth > 8) {
+		bits_per_pixel = max(max3(si->red_size + si->red_pos,
+					  si->green_size + si->green_pos,
+					  si->blue_size + si->blue_pos),
+				     si->rsvd_size + si->rsvd_pos);
+	} else {
+		bits_per_pixel = si->lfb_depth;
+	}
+
 	for (i = 0; i < ARRAY_SIZE(formats); ++i) {
-		f = &formats[i];
-		if (si->lfb_depth == f->bits_per_pixel &&
+		const struct simplefb_format *f = &formats[i];
+
+		if (f->transp.length)
+			continue; /* transparent formats are unsupported by VESA/EFI */
+
+		if (bits_per_pixel == f->bits_per_pixel &&
 		    si->red_size == f->red.length &&
 		    si->red_pos == f->red.offset &&
 		    si->green_size == f->green.length &&
 		    si->green_pos == f->green.offset &&
 		    si->blue_size == f->blue.length &&
-		    si->blue_pos == f->blue.offset &&
-		    si->rsvd_size == f->transp.length &&
-		    si->rsvd_pos == f->transp.offset) {
+		    si->blue_pos == f->blue.offset) {
 			mode->format = f->name;
 			mode->width = si->lfb_width;
 			mode->height = si->lfb_height;