bios: use image from PRAMIN in preference to PROM on NV50

There's at least one known case (rh#492658) where the DCB table present in
the VBIOS image from PROM is not suitable for use.  It contained all 16
entries filled, each entry valid in itself, but contradicting other entries.

The VBIOS image in PRAMIN however, still has all 16 entries filled, but the
first few entries now match what is present on the hardware, and the rest
are set as type 0xf, which we ignore.

1 files changed, 43 insertions, 23 deletions

diff --git a/src/nv_bios.c b/src/nv_bios.c
index 865b22d..b307fc6 100644
--- a/src/nv_bios.c
+++ b/src/nv_bios.c
@@ -187,42 +187,62 @@ static void load_vbios_pci(NVPtr pNv, uint8_t *data)
 #endif
 }
 
+struct methods {
+	const char desc[8];
+	void (*loadbios)(NVPtr, uint8_t *);
+	const bool rw;
+	int score;
+};
+
+static struct methods nv04_methods[] = {
+	{ "PROM", load_vbios_prom, false },
+	{ "PRAMIN", load_vbios_pramin, true },
+	{ "PCI ROM", load_vbios_pci, true }
+};
+
+static struct methods nv50_methods[] = {
+	{ "PRAMIN", load_vbios_pramin, true },
+	{ "PROM", load_vbios_prom, false },
+	{ "PCI ROM", load_vbios_pci, true }
+};
+
 static bool NVShadowVBIOS(ScrnInfoPtr pScrn, uint8_t *data)
 {
 	NVPtr pNv = NVPTR(pScrn);
-	struct methods {
-		const char desc[8];
-		void (*loadbios)(NVPtr, uint8_t *);
-		const bool rw;
-		int score;
-	} method[] = {
-		{ "PROM", load_vbios_prom, false },
-		{ "PRAMIN", load_vbios_pramin, true },
-		{ "PCI ROM", load_vbios_pci, true }
-	};
-	int i, testscore = 3;
-
-	for (i = 0; i < sizeof(method) / sizeof(struct methods); i++) {
+	struct methods *methods, *method;
+	int testscore = 3;
+
+	if (pNv->Architecture < NV_ARCH_50)
+		methods = nv04_methods;
+	else
+		methods = nv50_methods;
+
+	method = methods;
+	while (method->loadbios) {
 		NV_TRACE(pScrn, "Attempting to load BIOS image from %s\n",
-			 method[i].desc);
+			 method->desc);
 		data[0] = data[1] = 0;	/* avoid reuse of previous image */
-		method[i].loadbios(pNv, data);
-		method[i].score = score_vbios(pScrn, data, method[i].rw);
-		if (method[i].score == testscore)
+		method->loadbios(pNv, data);
+		method->score = score_vbios(pScrn, data, method->rw);
+		if (method->score == testscore)
 			return true;
+		method++;
 	}
 
-	while (--testscore > 0)
-		for (i = 0; i < sizeof(method) / sizeof(struct methods); i++)
-			if (method[i].score == testscore) {
+	while (--testscore > 0) {
+		method = methods;
+		while (method->loadbios) {
+			if (method->score == testscore) {
 				NV_TRACE(pScrn, "Using BIOS image from %s\n",
-					 method[i].desc);
-				method[i].loadbios(pNv, data);
+					 method->desc);
+				method->loadbios(pNv, data);
 				return true;
 			}
+			method++;
+		}
+	}
 
 	NV_ERROR(pScrn, "No valid BIOS image found\n");
-
 	return false;
 }