On 11/18/25 8:47 AM, Akhil P Oommen wrote:
> On 11/17/2025 9:17 PM, Neil Armstrong wrote:
>> On 11/17/25 16:02, Konrad Dybcio wrote:
>>> On 11/17/25 3:51 PM, Neil Armstrong wrote:
>>>> On plaforms with an a7xx GPU not supporting IFPC, the ifpc_reglist
>>>> if still deferenced in a7xx_patch_pwrup_reglist() which causes
>>>> a kernel crash:
>>>> Unable to handle kernel NULL pointer dereference at virtual address
>>>> 0000000000000008
>>>> ...
>>>> pc : a6xx_hw_init+0x155c/0x1e4c [msm]
>>>> lr : a6xx_hw_init+0x9a8/0x1e4c [msm]
>>>> ...
>>>> Call trace:
>>>> a6xx_hw_init+0x155c/0x1e4c [msm] (P)
>>>> msm_gpu_hw_init+0x58/0x88 [msm]
>>>> adreno_load_gpu+0x94/0x1fc [msm]
>>>> msm_open+0xe4/0xf4 [msm]
>>>> drm_file_alloc+0x1a0/0x2e4 [drm]
>>>> drm_client_init+0x7c/0x104 [drm]
>>>> drm_fbdev_client_setup+0x94/0xcf0 [drm_client_lib]
>>>> drm_client_setup+0xb4/0xd8 [drm_client_lib]
>>>> msm_drm_kms_post_init+0x2c/0x3c [msm]
>>>> msm_drm_init+0x1a4/0x228 [msm]
>>>> msm_drm_bind+0x30/0x3c [msm]
>>>> ...
>>>>
>>>> Check the validity of ifpc_reglist before deferencing the table
>>>> to setup the register values.
>>>>
>>>> Fixes: a6a0157cc68e ("drm/msm/a6xx: Enable IFPC on Adreno X1-85")
>>>> Signed-off-by: Neil Armstrong <[email protected]>
>>>> ---
>>>
>>> I think it should be fine to skip calling this func altogether
>>> if !ifpc || !pwrup_reglist
>>>
>>> Although ifpc && !pwrup_reglist should probably scream very loud
>
> That's correct. It is a weird combo.
>
>>
>> Sorry but why? pwrup_reglist was introduced way earlier than IFPC.
>
> Pwrup list is shared with preemption feature too. And preemption support
> was introduced before IFPC.
Sorry, I somehow erased that from my memory
Konrad
