As expected, things aren't as simple as hoped. Consequently, we have

no option but to use the smbios information to fill in the blanks.
It's a good thing UGA is a protocol of the past and GOP has all the
info we need.

Anyway, the logic has been tweaked a little to get the easier bits
of information up front. This includes the resolution and the frame
buffer address. Then we look at the smbios information and define
expected values as well as the missing bits (frame buffer offset and
stride). If the values obtained match the expect values, we fill in
the blanks and return. Otherwise we use the existing detection logic
to figure it out.

Rename the environment variables from uga_framebuffer abd uga_stride
to hw.efifb.address and hw.efifb.stride. The latter names are more
in line with other variable names.

We currently have hardcoded settings for:
1.  Mid-2007 iMac (iMac7,1)
2.  Late-2007 MacBook (MacBook3,1)

1 files changed, 76 insertions, 22 deletions

diff --git a/sys/boot/efi/loader/arch/amd64/framebuffer.c b/sys/boot/efi/loader/arch/amd64/framebuffer.c
index bd9b5eb..9a8dfdb 100644
--- a/sys/boot/efi/loader/arch/amd64/framebuffer.c
+++ b/sys/boot/efi/loader/arch/amd64/framebuffer.c
@@ -269,8 +269,10 @@ efifb_from_uga(struct efi_fb *efifb, EFI_UGA_DRAW_PROTOCOL *uga)
 	EFI_PCI_IO_PROTOCOL *pciio;
 	char *ev, *p;
 	EFI_STATUS status;
-	ssize_t ofs;
-	uint32_t np, horiz, vert, depth, refresh;
+	ssize_t offset;
+	uint64_t fbaddr, fbsize;
+	uint32_t horiz, vert, stride;
+	uint32_t np, depth, refresh;
 
 	status = uga->GetMode(uga, &horiz, &vert, &depth, &refresh);
 	if (EFI_ERROR(status))
@@ -285,6 +287,63 @@ efifb_from_uga(struct efi_fb *efifb, EFI_UGA_DRAW_PROTOCOL *uga)
 	efifb_mask_from_pixfmt(efifb, PixelBlueGreenRedReserved8BitPerColor,
 	    NULL);
 
+	/* pciio can be NULL on return! */
+	pciio = efifb_uga_get_pciio();
+
+	/* Try to find the frame buffer. */
+	status = efifb_uga_locate_framebuffer(pciio, &efifb->fb_addr,
+	    &efifb->fb_size);
+	if (EFI_ERROR(status)) {
+		efifb->fb_addr = 0;
+		efifb->fb_size = 0;
+	}
+
+	/*
+	 * There's no reliable way to detect the frame buffer or the
+	 * offset within the frame buffer of the visible region, nor
+	 * the stride. Our only option is to look at the system and
+	 * fill in the blanks based on that. Luckily, UGA was mostly
+	 * only used on Apple hardware. 
+	 */
+	offset = -1;
+	ev = getenv("smbios.system.maker");
+	if (ev != NULL && !strcmp(ev, "Apple Inc.")) {
+		ev = getenv("smbios.system.product");
+		if (ev != NULL && !strcmp(ev, "iMac7,1")) {
+			/* These are the expected values we should have. */
+			horiz = 1680;
+			vert = 1050;
+			fbaddr = 0xc0000000;
+			/* These are the missing bits. */
+			offset = 0x10000;
+			stride = 1728;
+		} else if (ev != NULL && !strcmp(ev, "MacBook3,1")) {
+			/* These are the expected values we should have. */
+			horiz = 1280;
+			vert = 800;
+			fbaddr = 0xc0000000;
+			/* These are the missing bits. */
+			offset = 0x0;
+			stride = 2048;
+		}
+	}
+
+	/*
+	 * If this is hardware we know, make sure that it looks familiar
+	 * before we accept our hardcoded values.
+	 */
+	if (offset >= 0 && efifb->fb_width == horiz &&
+	    efifb->fb_height == vert && efifb->fb_addr == fbaddr) {
+		efifb->fb_addr += offset;
+		efifb->fb_size -= offset;
+		efifb->fb_stride = stride;
+		return (0);
+	} else if (offset >= 0) {
+		printf("Hardware make/model known, but graphics not "
+		    "as expected.\n");
+		printf("Console may not work!\n");
+	}
+
 	/*
 	 * The stride is equal or larger to the width. Often it's the
 	 * next larger power of two. We'll start with that...
@@ -298,16 +357,11 @@ efifb_from_uga(struct efi_fb *efifb, EFI_UGA_DRAW_PROTOCOL *uga)
 		}
 	} while (np);
 
-	/* pciio can be NULL on return! */
-	pciio = efifb_uga_get_pciio();
-
-	ev = getenv("uga_framebuffer");
+	ev = getenv("hw.efifb.address");
 	if (ev == NULL) {
-		/* Try to find the frame buffer. */
-		status = efifb_uga_locate_framebuffer(pciio, &efifb->fb_addr,
-		    &efifb->fb_size);
-		if (EFI_ERROR(status)) {
-			printf("Please set uga_framebuffer!\n");
+		if (efifb->fb_addr == 0) {
+			printf("Please set hw.efifb.address and "
+			    "hw.efifb.stride.\n");
 			return (1);
 		}
 
@@ -328,30 +382,30 @@ efifb_from_uga(struct efi_fb *efifb, EFI_UGA_DRAW_PROTOCOL *uga)
 		 * to not appear to hang when we can't read from the
 		 * frame buffer.
 		 */
-		ofs = efifb_uga_find_pixel(uga, 0, pciio, efifb->fb_addr,
+		offset = efifb_uga_find_pixel(uga, 0, pciio, efifb->fb_addr,
 		    efifb->fb_size >> 8);
-		if (ofs == -1) {
+		if (offset == -1) {
 			printf("Unable to reliably detect frame buffer.\n");
-		} else if (ofs > 0) {
-			efifb->fb_addr += ofs;
-			efifb->fb_size -= ofs;
+		} else if (offset > 0) {
+			efifb->fb_addr += offset;
+			efifb->fb_size -= offset;
 		}
 	} else {
-		ofs = 0;
+		offset = 0;
 		efifb->fb_size = efifb->fb_height * efifb->fb_stride * 4;
 		efifb->fb_addr = strtoul(ev, &p, 0);
 		if (*p != '\0')
 			return (1);
 	}
 
-	ev = getenv("uga_stride");
+	ev = getenv("hw.efifb.stride");
 	if (ev == NULL) {
-		if (pciio != NULL && ofs != -1) {
+		if (pciio != NULL && offset != -1) {
 			/* Determine the stride. */
-			ofs = efifb_uga_find_pixel(uga, 1, pciio,
+			offset = efifb_uga_find_pixel(uga, 1, pciio,
 			    efifb->fb_addr, horiz * 8);
-			if (ofs != -1)
-				efifb->fb_stride = ofs >> 2;
+			if (offset != -1)
+				efifb->fb_stride = offset >> 2;
 		} else {
 			printf("Unable to reliably detect the stride.\n");
 		}