[PATCH] drm/nouveau/bios: fix offset calculation for BMPv1 bioses

[Ilia Mirkin]

The only BIOS on record that needs the 14 offset has a bios major
version 2 but BMP version 1.01. Another bunch of BIOSes that need the 18
offset have BMP version 2.01 or 5.01 or higher. So instead of looking at the
bios major version, look at the BMP version. BIOSes with BMP version 0
do not contain a detectable script, so always return 0 for them.

See https://bugs.freedesktop.org/show_bug.cgi?id=68835

Reported-by: Mauro Molinari <mauromol at tiscali.it>
Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
---

Unfortunately the bug reporter doesn't really know how to compile kernels and
my bet is that the system his NV04 is in isn't exactly top-of-the-line, so a
kernel compile would take forever.

I've made similar changes in nvbios, and it seems to now handle every
nv04/nv05 bios in our repo, in addition to Mauro's, so I think these changes
should be safe-ish. However I'm not tagging for stable yet, in case things
don't pan out the way I expected. If Mauro tests a kernel with this and all's
well, then I'll send a separate request to stable-ify this patch.

I'm betting that some old code used to check the bmp_version_major against 2,
but that got changed to bios major in one of the rewrites, although I didn't
go digging.

 drivers/gpu/drm/nouveau/core/subdev/bios/init.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/core/subdev/bios/init.c b/drivers/gpu/drm/nouveau/core/subdev/bios/init.c
index 9f5b81e..df1b1b4 100644
--- a/drivers/gpu/drm/nouveau/core/subdev/bios/init.c
+++ b/drivers/gpu/drm/nouveau/core/subdev/bios/init.c
@@ -365,13 +365,13 @@ static u16
 init_script(struct nouveau_bios *bios, int index)
 {
 	struct nvbios_init init = { .bios = bios };
-	u16 data;
+	u16 bmp_ver = bmp_version(bios), data;
 
-	if (bmp_version(bios) && bmp_version(bios) < 0x0510) {
-		if (index > 1)
+	if (bmp_ver && bmp_ver < 0x0510) {
+		if (index > 1 || bmp_ver < 0x0100)
 			return 0x0000;
 
-		data = bios->bmp_offset + (bios->version.major < 2 ? 14 : 18);
+		data = bios->bmp_offset + (bmp_ver < 0x0200 ? 14 : 18);
 		return nv_ro16(bios, data + (index * 2));
 	}
 
-- 
1.8.3.2