[V2] drm/loongson: Error out if no VRAM detected

[Sui Jingfeng]

Hi,


On 2024/1/24 18:16, Huacai Chen wrote:
> If there is no VRAM (it can be true if there is a discreted card, this
> is probably a hardware configuration issue in BIOS but it is observed in
> GDC-1401 laptop, L71 laptop and some Loongson-3C5000L based servers), 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.
>
> Tested-by: Xiaotian Wu <wuxiaotian at loongson.cn>
> Signed-off-by: Huacai Chen <chenhuacai at loongson.cn>


By the way, sending patch should Cc Maxime and Thomas in the future.
Since this patch is small patch, not a big deal, so it probably okay.

This serve as a basic sanity check, hopes this helps to mitigate the pains.


Reviewed-by: Sui Jingfeng <sui.jingfeng at linux.dev>