drm/nouveau/bios: return actual size of the buffer retrieved via _ROM

Fixes detection of a failed attempt at fetching the entire ROM image
in one-shot (a violation of the spec, that works a lot of the time).

Tested on a HP Zbook 15 G2.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c b/drivers/gpu/drm/nouveau/nouveau_acpi.c
index 8b8332e46f24..d5e6938cc6bc 100644
--- a/drivers/gpu/drm/nouveau/nouveau_acpi.c
+++ b/drivers/gpu/drm/nouveau/nouveau_acpi.c
@@ -367,6 +367,7 @@ static int nouveau_rom_call(acpi_handle rom_handle, uint8_t *bios,
                 return -ENODEV;
         }
         obj = (union acpi_object *)buffer.pointer;
+        len = min(len, (int)obj->buffer.length);
         memcpy(bios+offset, obj->buffer.pointer, len);
         kfree(buffer.pointer);
         return len;