[Nouveau] [BUG][NOUVEAU] G70 broken since 5.10-rc1

[Christian König]

Hi Mark,

Am 26.11.20 um 13:26 schrieb Mark Hounschell:
> On 11/26/20 7:05 AM, Christian König wrote:
>> Hi Mark,
>>
>> Am 26.11.20 um 10:59 schrieb Mark Hounschell:
>>> On 11/26/20 3:35 AM, Christian König wrote:
>>>>> I'm running an older "NVIDIA Corporation G70 [GeForce 7800 GT] 
>>>>> (rev a1)" card in a newer BIOSTAR B550GTA MB. Kernel 5.10-rcx does 
>>>>> not work. I get no virtual consoles or X screen.
>>
>> thanks for the dmesg.
>>
>> Problem is I don't have the slightest idea what's going wrong here :)
>>
>> The code should be functional identical, it was just moved from TTM 
>> to nouveau, so we are missing some detail in the handling.
>>
>> Can you run the following test for me: First you need to disable 
>> loading of the nouveau kernel module by adding 
>> modprobe.blacklist=nouveau to the kernel command line.
>>
>> Then log into the system over the network and run the following 
>> commands:
>>
>> sudo modprobe ttm
>> sudo bash -c "echo 'ttm_bo_kmap' > 
>> /sys/kernel/debug/tracing/set_graph_function"
>> sudo bash -c "echo function_graph > 
>> /sys/kernel/debug/tracing/current_tracer"
>> sudo modprobe nouveau
>> sudo bash -c "cat /sys/kernel/debug/tracing/trace" > trace.log
>>
>> Please then send me the resulting trace.log file so that I can 
>> investigate why mapping the framebuffer fails during driver load.
>>
>> Thanks in advance,
>> Christian.
>
> I hope this is what you need. I do normally turn off a lot of debug 
> features. Let me know if I need to change the kernel config.

It was not what I had expected but it pointed me in the right direction. 
I think I've found the problem, it's just an uninitialized return value 
for your hardware generation.

Please try the attached patch and let me know if it fixes the problem.

Thanks in advance,
Christian.
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