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

[Matthew Auld]

On 11/04/2023 19:31, Lucas De Marchi wrote:
> 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.

We also have the above drm_info "Using a reduced BAR size.." message, 
which will appear for the user.

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

Thanks. I'll also drop the comment for now.

> 
> 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
>>