Nouveau - Aug 2019 - [PATCH] volt: Fix for some cards having 0 maximum voltage

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 at linux.intel.com>
Signed-off-by: Mark Menzynski <mmenzyns at redhat.com>
---
 drm/nouveau/nvkm/subdev/bios/volt.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drm/nouveau/nvkm/subdev/bios/volt.c
b/drm/nouveau/nvkm/subdev/bios/volt.c
index 7143ea46..33a9fb5a 100644
--- a/drm/nouveau/nvkm/subdev/bios/volt.c
+++ b/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);
-- 
2.21.0

although I'd like to have a deeper understanding of this table, I
think it's fine as it is right now and this actually does fix
something without causing any issues (as far as we know of)

Reviewed-by: Karol Herbst <kherbst at redhat.com>

On Fri, Aug 2, 2019 at 11:21 AM Mark Menzynski <mmenzyns at redhat.com>
wrote:
>
> 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 at linux.intel.com>
> Signed-off-by: Mark Menzynski <mmenzyns at redhat.com>
> ---
>  drm/nouveau/nvkm/subdev/bios/volt.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drm/nouveau/nvkm/subdev/bios/volt.c
b/drm/nouveau/nvkm/subdev/bios/volt.c
> index 7143ea46..33a9fb5a 100644
> --- a/drm/nouveau/nvkm/subdev/bios/volt.c
> +++ b/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);
> --
> 2.21.0
>
> _______________________________________________
> Nouveau mailing list
> Nouveau at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/nouveau