efifb: Support overriding fields FW tells us with the DMI data.

Some machines apparently give us bogus linelength/stride/pitch data, so
we need to support letting the DMI table override the supplied data.

I bet you can't guess whose machines I'm talking about.
Signed-off-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

drivers/video/efifb.c

@@ -68,41 +68,48 @@ enum {
 	M_UNKNOWN	/* placeholder */
 };
 
+#define OVERRIDE_NONE	0x0
+#define OVERRIDE_BASE	0x1
+#define OVERRIDE_STRIDE	0x2
+#define OVERRIDE_HEIGHT	0x4
+#define OVERRIDE_WIDTH	0x8
+
 static struct efifb_dmi_info {
 	char *optname;
 	unsigned long base;
 	int stride;
 	int width;
 	int height;
+	int flags;
 } dmi_list[] __initdata = {
-	[M_I17] = { "i17", 0x80010000, 1472 * 4, 1440, 900 },
-	[M_I20] = { "i20", 0x80010000, 1728 * 4, 1680, 1050 }, /* guess */
-	[M_I20_SR] = { "imac7", 0x40010000, 1728 * 4, 1680, 1050 },
-	[M_I24] = { "i24", 0x80010000, 2048 * 4, 1920, 1200 }, /* guess */
-	[M_I24_8_1] = { "imac8", 0xc0060000, 2048 * 4, 1920, 1200 },
-	[M_I24_10_1] = { "imac10", 0xc0010000, 2048 * 4, 1920, 1080 },
-	[M_I27_11_1] = { "imac11", 0xc0010000, 2560 * 4, 2560, 1440 },
-	[M_MINI]= { "mini", 0x80000000, 2048 * 4, 1024, 768 },
-	[M_MINI_3_1] = { "mini31", 0x40010000, 1024 * 4, 1024, 768 },
-	[M_MINI_4_1] = { "mini41", 0xc0010000, 2048 * 4, 1920, 1200 },
-	[M_MB] = { "macbook", 0x80000000, 2048 * 4, 1280, 800 },
-	[M_MB_5_1] = { "macbook51", 0x80010000, 2048 * 4, 1280, 800 },
-	[M_MB_6_1] = { "macbook61", 0x80010000, 2048 * 4, 1280, 800 },
-	[M_MB_7_1] = { "macbook71", 0x80010000, 2048 * 4, 1280, 800 },
-	[M_MBA] = { "mba", 0x80000000, 2048 * 4, 1280, 800 },
-	[M_MBP] = { "mbp", 0x80010000, 1472 * 4, 1440, 900 },
-	[M_MBP_2] = { "mbp2", 0, 0, 0, 0 }, /* placeholder */
-	[M_MBP_2_2] = { "mbp22", 0x80010000, 1472 * 4, 1440, 900 },
-	[M_MBP_SR] = { "mbp3", 0x80030000, 2048 * 4, 1440, 900 },
-	[M_MBP_4] = { "mbp4", 0xc0060000, 2048 * 4, 1920, 1200 },
-	[M_MBP_5_1] = { "mbp51", 0xc0010000, 2048 * 4, 1440, 900 },
-	[M_MBP_5_2] = { "mbp52", 0xc0010000, 2048 * 4, 1920, 1200 },
-	[M_MBP_5_3] = { "mbp53", 0xd0010000, 2048 * 4, 1440, 900 },
-	[M_MBP_6_1] = { "mbp61", 0x90030000, 2048 * 4, 1920, 1200 },
-	[M_MBP_6_2] = { "mbp62", 0x90030000, 2048 * 4, 1680, 1050 },
-	[M_MBP_7_1] = { "mbp71", 0xc0010000, 2048 * 4, 1280, 800 },
-	[M_MBP_8_2] = { "mbp82", 0x90010000, 1472 * 4, 1440, 900 },
-	[M_UNKNOWN] = { NULL, 0, 0, 0, 0 }
+	[M_I17] = { "i17", 0x80010000, 1472 * 4, 1440, 900, OVERRIDE_NONE },
+	[M_I20] = { "i20", 0x80010000, 1728 * 4, 1680, 1050, OVERRIDE_NONE }, /* guess */
+	[M_I20_SR] = { "imac7", 0x40010000, 1728 * 4, 1680, 1050, OVERRIDE_NONE },
+	[M_I24] = { "i24", 0x80010000, 2048 * 4, 1920, 1200, OVERRIDE_NONE }, /* guess */
+	[M_I24_8_1] = { "imac8", 0xc0060000, 2048 * 4, 1920, 1200, OVERRIDE_NONE },
+	[M_I24_10_1] = { "imac10", 0xc0010000, 2048 * 4, 1920, 1080, OVERRIDE_NONE },
+	[M_I27_11_1] = { "imac11", 0xc0010000, 2560 * 4, 2560, 1440, OVERRIDE_NONE },
+	[M_MINI]= { "mini", 0x80000000, 2048 * 4, 1024, 768, OVERRIDE_NONE },
+	[M_MINI_3_1] = { "mini31", 0x40010000, 1024 * 4, 1024, 768, OVERRIDE_NONE },
+	[M_MINI_4_1] = { "mini41", 0xc0010000, 2048 * 4, 1920, 1200, OVERRIDE_NONE },
+	[M_MB] = { "macbook", 0x80000000, 2048 * 4, 1280, 800, OVERRIDE_NONE },
+	[M_MB_5_1] = { "macbook51", 0x80010000, 2048 * 4, 1280, 800, OVERRIDE_NONE },
+	[M_MB_6_1] = { "macbook61", 0x80010000, 2048 * 4, 1280, 800, OVERRIDE_NONE },
+	[M_MB_7_1] = { "macbook71", 0x80010000, 2048 * 4, 1280, 800, OVERRIDE_NONE },
+	[M_MBA] = { "mba", 0x80000000, 2048 * 4, 1280, 800, OVERRIDE_NONE },
+	[M_MBP] = { "mbp", 0x80010000, 1472 * 4, 1440, 900, OVERRIDE_NONE },
+	[M_MBP_2] = { "mbp2", 0, 0, 0, 0, OVERRIDE_NONE }, /* placeholder */
+	[M_MBP_2_2] = { "mbp22", 0x80010000, 1472 * 4, 1440, 900, OVERRIDE_NONE },
+	[M_MBP_SR] = { "mbp3", 0x80030000, 2048 * 4, 1440, 900, OVERRIDE_NONE },
+	[M_MBP_4] = { "mbp4", 0xc0060000, 2048 * 4, 1920, 1200, OVERRIDE_NONE },
+	[M_MBP_5_1] = { "mbp51", 0xc0010000, 2048 * 4, 1440, 900, OVERRIDE_NONE },
+	[M_MBP_5_2] = { "mbp52", 0xc0010000, 2048 * 4, 1920, 1200, OVERRIDE_NONE },
+	[M_MBP_5_3] = { "mbp53", 0xd0010000, 2048 * 4, 1440, 900, OVERRIDE_NONE },
+	[M_MBP_6_1] = { "mbp61", 0x90030000, 2048 * 4, 1920, 1200, OVERRIDE_NONE },
+	[M_MBP_6_2] = { "mbp62", 0x90030000, 2048 * 4, 1680, 1050, OVERRIDE_NONE },
+	[M_MBP_7_1] = { "mbp71", 0xc0010000, 2048 * 4, 1280, 800, OVERRIDE_NONE },
+	[M_MBP_8_2] = { "mbp82", 0x90010000, 1472 * 4, 1440, 900, OVERRIDE_NONE },
+	[M_UNKNOWN] = { NULL, 0, 0, 0, 0, OVERRIDE_NONE }
 };
 
 static int set_system(const struct dmi_system_id *id);
@@ -157,16 +164,22 @@ static const struct dmi_system_id dmi_system_table[] __initconst = {
 	{},
 };
 
+#define choose_value(dmivalue, fwvalue, field, flags) ({	\
+		typeof(fwvalue) _ret_ = fwvalue;		\
+		if ((flags) & (field))				\
+			_ret_ = dmivalue;			\
+		else if ((fwvalue) == 0)			\
+			_ret_ = dmivalue;			\
+		_ret_;						\
+	})
+
 static int set_system(const struct dmi_system_id *id)
 {
 	struct efifb_dmi_info *info = id->driver_data;
-	if (info->base == 0)
-		return 0;
 
-	printk(KERN_INFO "efifb: dmi detected %s - framebuffer at %p "
-			 "(%dx%d, stride %d)\n", id->ident,
-			 (void *)info->base, info->width, info->height,
-			 info->stride);
+	if (info->base == 0 && info->height == 0 && info->width == 0
+			&& info->stride == 0)
+		return 0;
 
 	/* Trust the bootloader over the DMI tables */
 	if (screen_info.lfb_base == 0) {
@@ -174,11 +187,14 @@ static int set_system(const struct dmi_system_id *id)
 		struct pci_dev *dev = NULL;
 		int found_bar = 0;
 #endif
-		screen_info.lfb_base = info->base;
+		if (info->base) {
+			screen_info.lfb_base = choose_value(info->base,
+				screen_info.lfb_base, OVERRIDE_BASE,
+				info->flags);
 
 #if defined(CONFIG_PCI)
-		/* make sure that the address in the table is actually on a
-		 * VGA device's PCI BAR */
+			/* make sure that the address in the table is actually
+			 * on a VGA device's PCI BAR */
 
 			for_each_pci_dev(dev) {
 				int i;
@@ -201,13 +217,17 @@ static int set_system(const struct dmi_system_id *id)
 				screen_info.lfb_base = 0;
 #endif
 		}
+	}
 	if (screen_info.lfb_base) {
-		if (screen_info.lfb_linelength == 0)
-			screen_info.lfb_linelength = info->stride;
-		if (screen_info.lfb_width == 0)
-			screen_info.lfb_width = info->width;
-		if (screen_info.lfb_height == 0)
-			screen_info.lfb_height = info->height;
+		screen_info.lfb_linelength = choose_value(info->stride,
+			screen_info.lfb_linelength, OVERRIDE_STRIDE,
+			info->flags);
+		screen_info.lfb_width = choose_value(info->width,
+			screen_info.lfb_width, OVERRIDE_WIDTH,
+			info->flags);
+		screen_info.lfb_height = choose_value(info->height,
+			screen_info.lfb_height, OVERRIDE_HEIGHT,
+			info->flags);
 		if (screen_info.orig_video_isVGA == 0)
 			screen_info.orig_video_isVGA = VIDEO_TYPE_EFI;
 	} else {
@@ -217,6 +237,13 @@ static int set_system(const struct dmi_system_id *id)
 		screen_info.orig_video_isVGA = 0;
 		return 0;
 	}
+
+	printk(KERN_INFO "efifb: dmi detected %s - framebuffer at %p "
+			 "(%dx%d, stride %d)\n", id->ident,
+			 (void *)screen_info.lfb_base, screen_info.lfb_width,
+			 screen_info.lfb_height, screen_info.lfb_linelength);
+
+
 	return 1;
 }