From a1af2afbd244089560794c260b2d4326a86e39b6 Mon Sep 17 00:00:00 2001
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: v5.4-rc1
References: bsc#1152489

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>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/nouveau/nvkm/subdev/bios/volt.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/volt.c b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/volt.c
index 7143ea4611aa..33a9fb5ac558 100644
--- 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, u8 *ver, u8 *hdr, u8 *cnt, u8 *len,
 		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);
-- 
2.28.0