drm/loongson: Error out if no VRAM detected

[Sui Jingfeng]

On 2024/1/19 18:40, Huacai Chen wrote:
> If there is no VRAM (it is true if there is a discreted card), we get
> such an error and Xorg fails to start:
>
> [  136.401131] loongson 0000:00:06.1: [drm] *ERROR* Requesting(0MiB) failed
> [  137.444342] loongson 0000:00:06.1: [drm] *ERROR* Requesting(0MiB) failed
> [  138.871166] loongson 0000:00:06.1: [drm] *ERROR* Requesting(0MiB) failed
> [  140.444078] loongson 0000:00:06.1: [drm] *ERROR* Requesting(0MiB) failed
> [  142.403993] loongson 0000:00:06.1: [drm] *ERROR* Requesting(0MiB) failed
> [  143.970625] loongson 0000:00:06.1: [drm] *ERROR* Requesting(0MiB) failed
> [  145.862013] loongson 0000:00:06.1: [drm] *ERROR* Requesting(0MiB) failed
>
> So in lsdc_get_dedicated_vram() we error out if no VRAM (or VRAM is less
> than 1MB which is also an unusable case) detected.
>
> Signed-off-by: Huacai Chen <chenhuacai at loongson.cn>
> ---
>   drivers/gpu/drm/loongson/lsdc_drv.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/loongson/lsdc_drv.c b/drivers/gpu/drm/loongson/lsdc_drv.c
> index 89ccc0c43169..d8ff60b46abe 100644
> --- a/drivers/gpu/drm/loongson/lsdc_drv.c
> +++ b/drivers/gpu/drm/loongson/lsdc_drv.c
> @@ -184,7 +184,7 @@ static int lsdc_get_dedicated_vram(struct lsdc_device *ldev,
>   	drm_info(ddev, "Dedicated vram start: 0x%llx, size: %uMiB\n",
>   		 (u64)base, (u32)(size >> 20));
>   
> -	return 0;
> +	return (size > SZ_1M) ? 0 : -ENODEV;


I forget to tell you that you probably should return ENOSPC at here,
which stand for no space left on device, not the ENODEV.