drm/loongson: Error out if no VRAM detected

[Sui Jingfeng]

Hi,


CCing Li Chao <lichao at loongson.cn>


On 2024/1/21 15:07, Katyusha wrote:
> Hi,
>
> On 2024/1/21 5:28, Sui JIngfeng wrote:
>> Hi,
>>
>>
>> On 2024/1/20 20:01, Katyusha wrote:
>>>
>>> Hi,
>>>
>>> This patch works fine with my Loongson 3A5000M laptop (L71), which 
>>> has a 7A1000 chipset without VRAM.
>>>
>>>
>>
>> Can you give more details about the hardware configuration about this 
>> laptop?
>> For example, by using 'lspci | grep VGA' command. I want to make sure 
>> if the
>> integrated display controller are there.
>>
>>
>> Normally, the integrated graphics should not be used if there is no 
>> dedicated
>> VRAM equipped. And the platform BIOS should disable it.
>>
> Here's my result of lspci:
>
> $ sudo lspci -k | grep VGA
> 00:06.1 VGA compatible controller: Loongson Technology LLC DC (Display 
> Controller) (rev 01)
> 07:00.0 VGA compatible controller: Advanced Micro Devices, Inc. 
> [AMD/ATI] Oland [Radeon HD 8570 / R5 430 OEM / R7 240/340 / Radeon 520 
> OEM] (rev 87)
>

Thanks a lot for feedback, please feed this back to Loongson UEFI firmware team.
Update the firmware, as this is not the right way to fix a bug.

When Loongson laptop or notebook is equipped with a Radeon GPU,
the integrated graphics will not be used. Besides don't has a
dedicated VRAM, it also don't has a external video transmitters.
Therefore, the integrate graphics are completely not usable.
Please disable it on such cases.