[Intel-xe] [PATCH] drm/xe/mmio: stop incorrectly triggering drm_warn

[Lucas De Marchi]

On Tue, Apr 11, 2023 at 11:04:58AM +0100, Matthew Auld wrote:
>CI keeps triggering:
>
>xe 0000:03:00.0: [drm] Restricting VRAM size to PCI resource size
>(0x400000000->0x3fa000000)
>
>Due to usable_size vs vram_size differences. However, we only want to
>trigger the drm_warn() to let developers know that the system they are
>using is going clamp the VRAM size to match the IO size, where they can
>likely only use 256M of VRAM. Once we properly support small-bar we can
>drop this.
>
>Signed-off-by: Matthew Auld <matthew.auld at intel.com>
>Cc: Gwan-gyeong Mun <gwan-gyeong.mun at intel.com>
>---
> drivers/gpu/drm/xe/xe_mmio.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
>diff --git a/drivers/gpu/drm/xe/xe_mmio.c b/drivers/gpu/drm/xe/xe_mmio.c
>index 5cacaa05759a..7d62fae25bb4 100644
>--- a/drivers/gpu/drm/xe/xe_mmio.c
>+++ b/drivers/gpu/drm/xe/xe_mmio.c
>@@ -228,9 +228,9 @@ int xe_mmio_probe_vram(struct xe_device *xe)
> 	else if (xe->mem.vram.io_size < usable_size && !xe_force_vram_bar_size)
> 		drm_info(&xe->drm, "Using a reduced BAR size of %lluMiB. Consider enabling 'Resizable BAR' support in your BIOS.\n",
> 			 (u64)xe->mem.vram.size >> 20);
>-	if (xe->mem.vram.size < vram_size)
>+	if (usable_size > xe->mem.vram.io_size) /* TODO: remove once we properly support small-bar */

The fix looks good,  but I don´t think the TODO makes sense as it has
perf and uapi implications. Maybe we could downgrade to a info/notice
when small-bar is fully supported, but not dropping.

For now, I'd merge this without this comment:
	
Reviewed-by: Lucas De Marchi <lucas.demarchi at intel.com>

Lucas De Marchi

> 		drm_warn(&xe->drm, "Restricting VRAM size to PCI resource size (0x%llx->0x%llx)\n",
>-			 vram_size, (u64)xe->mem.vram.size);
>+			 usable_size, xe->mem.vram.io_size);
>
> 	xe->mem.vram.mapping = ioremap_wc(xe->mem.vram.io_start, xe->mem.vram.io_size);
> 	xe->mem.vram.size = min_t(u64, xe->mem.vram.size, usable_size);
>-- 
>2.39.2
>