From: Mark Menzynski <mmenzyns@redhat.com>
Date: Fri, 2 Aug 2019 11:21:00 +0200
Subject: drm/nouveau/volt: Fix for some cards having 0 maximum voltage
Git-commit: a1af2afbd244089560794c260b2d4326a86e39b6
Patch-mainline: 5.4-rc1
References: bnc#1151927 5.3.5

Some, mostly Fermi, vbioses appear to have zero max voltage. That causes Nouveau to not parse voltage entries, thus users not being able to set higher clocks.

When changing this value Nvidia driver still appeared to ignore it, and I wasn't able to find out why, thus the code is ignoring the value if it is zero.

CC: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Mark Menzynski <mmenzyns@redhat.com>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/gpu/drm/nouveau/nvkm/subdev/bios/volt.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/volt.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/volt.c
@@ -96,6 +96,8 @@ nvbios_volt_parse(struct nvkm_bios *bios
 		info->min     = min(info->base,
 				    info->base + info->step * info->vidmask);
 		info->max     = nvbios_rd32(bios, volt + 0x0e);
+		if (!info->max)
+			info->max = max(info->base, info->base + info->step * info->vidmask);
 		break;
 	case 0x50:
 		info->min     = nvbios_rd32(bios, volt + 0x0a);