EDID: add fields specialized to the needs of framebuffers

Now that we have horizontal display areas that are not multiples of 32  bytes,
things are more complex. We add three struct members (x, y resolution and
bytes per line) which are to be filled in by the mainboard as it sets the mode.

In future, the EDID code may take a stab at initializing these but the values are
context-dependent.

Change-Id: Ib9102d6bbf8c66931f5adb1029a04b881a982cfe
Signed-off-by: Ronald G. Minnich <rminnich@google.com>
Reviewed-on: https://gerrit.chromium.org/gerrit/60514
Tested-by: Ronald G. Minnich <rminnich@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Commit-Queue: Ronald G. Minnich <rminnich@chromium.org>
Reviewed-on: http://review.coreboot.org/4336
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

2 files changed, 28 insertions, 4 deletions

diff --git a/src/include/edid.h b/src/include/edid.h
index 7d4736dc33..ce1f615709 100644
--- a/src/include/edid.h
+++ b/src/include/edid.h
@@ -55,6 +55,14 @@ struct edid {
 	unsigned int vso;
 	unsigned int vspw;
 	unsigned int vborder;
+	/* 3 variables needed for coreboot framebuffer.
+	 * In most cases, they are the same as the ha
+	 * and va variables, but not always, as in the
+	 * case of a 1366 wide display.
+	 */
+	u32 x_resolution;
+	u32 y_resolution;
+	u32 bytes_per_line;
 	/* it is unlikely we need these things. */
 	/* if one of these is non-zero, use that one. */
 	unsigned int aspect_landscape;
diff --git a/src/lib/edid.c b/src/lib/edid.c
index d0e8b98b52..aa12596d89 100644
--- a/src/lib/edid.c
+++ b/src/lib/edid.c
@@ -457,6 +457,23 @@ detailed_block(struct edid *out, unsigned char *x, int in_extension)
 		out->vso = ((x[10] >> 4) + ((x[11] & 0x0C) << 2));
 		out->vspw = ((x[10] & 0x0F) + ((x[11] & 0x03) << 4));
 		out->vborder = x[16];
+		/* set up some reasonable defaults for payloads.
+		 * We observe that most modern chipsets we work with
+		 * tend to support rgb888 without regard to the
+		 * panel bits per color or other settings. The rgb888
+		 * is a convenient layout for software because
+		 * it avoids the messy bit stuffing of rgb565 or rgb444.
+		 * It makes a reasonable trade of memory for speed.
+		 * So, set up the default for
+		 * 32 bits per pixel
+		 * rgb888 (i.e. no alpha, but pixels on 32-bit boundaries)
+		 * The mainboard can modify these if needed, though
+		 * we have yet to see a case where that will happen.
+		 */
+		out->bpp = 32;
+		out->x_resolution = ALIGN(out->ha * ((out->bpp + 7) / 8),64) / (out->bpp/8);
+		out->y_resolution = out->va;
+		out->bytes_per_line = ALIGN(out->ha * ((out->bpp + 7) / 8),64);
 		printk(BIOS_SPEW, "Did detailed timing\n");
 	}
 	did_detailed_timing = 1;
@@ -1398,8 +1415,9 @@ int decode_edid(unsigned char *edid, int size, struct edid *out)
 void set_vbe_mode_info_valid(struct edid *edid, uintptr_t fb_addr)
 {
 	edid_fb.physical_address = fb_addr;
-	edid_fb.x_resolution = edid->ha;
-	edid_fb.y_resolution = edid->va;
+	edid_fb.x_resolution = edid->x_resolution;
+	edid_fb.y_resolution = edid->y_resolution;
+	edid_fb.bytes_per_line = edid->bytes_per_line;
 	/* In the case of (e.g.) 24bpp, the convention nowadays
 	 * seems to be to round it up to the nearest reasonable
 	 * boundary, because otherwise the byte-packing is hideous.
@@ -1416,7 +1434,6 @@ void set_vbe_mode_info_valid(struct edid *edid, uintptr_t fb_addr)
 	case 32:
 	case 24:
 		/* packed into 4-byte words */
-		edid_fb.bytes_per_line = edid->ha * 4;
 		edid_fb.red_mask_pos = 16;
 		edid_fb.red_mask_size = 8;
 		edid_fb.green_mask_pos = 8;
@@ -1426,7 +1443,6 @@ void set_vbe_mode_info_valid(struct edid *edid, uintptr_t fb_addr)
 		break;
 	case 16:
 		/* packed into 2-byte words */
-		edid_fb.bytes_per_line = edid->ha * 2;
 		edid_fb.red_mask_pos = 12;
 		edid_fb.red_mask_size = 4;
 		edid_fb.green_mask_pos = 8;