[PATCH] fbdev: Resurrect hooks to get EDID from firmware

For the i386, code is already present in video.S that gets the EDID from the
video BIOS.  Make this visible so drivers can also use this data as fallback
when i2c does not work.

To ensure that the EDID block is returned for the primary graphics adapter
only, by check if the IORESOURCE_ROM_SHADOW flag is set.

Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 39 insertions, 3 deletions

diff --git a/arch/i386/boot/video.S b/arch/i386/boot/video.S
index 02bf625a681b..92f669470142 100644
--- a/arch/i386/boot/video.S
+++ b/arch/i386/boot/video.S
@@ -1949,7 +1949,7 @@ store_edid:
         movw    $0x4f15, %ax                    # do VBE/DDC
         movw    $0x01, %bx
         movw    $0x00, %cx
-        movw    $0x01, %dx
+        movw    $0x00, %dx
         movw    $0x140, %di
         int     $0x10
 
diff --git a/arch/i386/kernel/setup.c b/arch/i386/kernel/setup.c
index a659d274914c..fa0c69eb937a 100644
--- a/arch/i386/kernel/setup.c
+++ b/arch/i386/kernel/setup.c
@@ -139,6 +139,7 @@ struct sys_desc_table_struct {
         unsigned char table[0];
 };
 struct edid_info edid_info;
+EXPORT_SYMBOL_GPL(edid_info);
 struct ist_info ist_info;
 #if defined(CONFIG_X86_SPEEDSTEP_SMI) || \
         defined(CONFIG_X86_SPEEDSTEP_SMI_MODULE)
diff --git a/drivers/video/fbmon.c b/drivers/video/fbmon.c
index c2718bb94949..791bec3d672a 100644
--- a/drivers/video/fbmon.c
+++ b/drivers/video/fbmon.c
@@ -29,6 +29,7 @@
 #include <linux/tty.h>
 #include <linux/fb.h>
 #include <linux/module.h>
+#include <video/edid.h>
 #ifdef CONFIG_PPC_OF
 #include <linux/pci.h>
 #include <asm/prom.h>
@@ -1251,9 +1252,41 @@ int fb_validate_mode(const struct fb_var_screeninfo *var, struct fb_info *info)
                 -EINVAL : 0;
 }
 
+#if defined(__i386__)
+#include <linux/pci.h>
+
+/*
+ * We need to ensure that the EDID block is only returned for
+ * the primary graphics adapter.
+ */
+
+const unsigned char *fb_firmware_edid(struct device *device)
+{
+        struct pci_dev *dev = NULL;
+        struct resource *res = NULL;
+        unsigned char *edid = NULL;
+
+        if (device)
+                dev = to_pci_dev(device);
+
+        if (dev)
+                res = &dev->resource[PCI_ROM_RESOURCE];
+
+        if (res && res->flags & IORESOURCE_ROM_SHADOW)
+                edid = edid_info.dummy;
+
+        return edid;
+}
+#else
+const unsigned char *fb_firmware_edid(struct device *device)
+{
+        return NULL;
+}
+#endif /* _i386_ */
+
 EXPORT_SYMBOL(fb_parse_edid);
 EXPORT_SYMBOL(fb_edid_to_monspecs);
-
+EXPORT_SYMBOL(fb_firmware_edid);
 EXPORT_SYMBOL(fb_get_mode);
 EXPORT_SYMBOL(fb_validate_mode);
 EXPORT_SYMBOL(fb_destroy_modedb);
diff --git a/include/linux/fb.h b/include/linux/fb.h
index 70da819df0f5..e3e16f43b1bb 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -859,7 +859,9 @@ extern int fb_get_mode(int flags, u32 val, struct fb_var_screeninfo *var,
 extern int fb_validate_mode(const struct fb_var_screeninfo *var,
                             struct fb_info *info);
 extern int fb_parse_edid(unsigned char *edid, struct fb_var_screeninfo *var);
-extern void fb_edid_to_monspecs(unsigned char *edid, struct fb_monspecs *specs);
+extern const unsigned char *fb_firmware_edid(struct device *device);
+extern void fb_edid_to_monspecs(unsigned char *edid,
+                                struct fb_monspecs *specs);
 extern void fb_destroy_modedb(struct fb_videomode *modedb);
 
 /* drivers/video/modedb.c */