[linux-yocto] [kernel-cache][yocto-4.12][PATCH] features/i915/i915.cfg: compile i915 as a module

[Bruce Ashfield]

On 12/05/2017 09:10 PM, Liwei Song wrote:
> 
> 
> On 12/06/2017 06:26 AM, Bruce Ashfield wrote:
>> On 12/04/2017 08:16 PM, Liwei Song wrote:
>>> Set i915 as a moudle to trigger the firmware load
>>
>> typo: module
>>
>>> at the same time the module is loaded.
>>>
>>> This can aviod i915 driver load rootfs's firmware before
>>> rootfs was mounted error.
>>
>> I'm not following this problem description, can you rephrase ?
>> Is it a timing problem between the driving starting (as the
>> built in) and it triggering a firmware load (that fails due
>> to the rootfs not being ready) ?
> 
> Yes, it is a timing problem, how about rephrase it as following:
> 
> This can aviod a timing problem between the driver starting

s/aviod/avoid/

> and it triggering a firmware load, after compile it as module
> i915 driver will start after the rootfs is ready, then the
> firmware store in /lib/firmware/ can be load successful by
> i915 driver.
> 

But yes, that log is good for a v2.

>   
> 
>>
>> presumably the i915 was built in for a reason, i.e. so it
>> is available in early boot without the need to load a module.
>> And this change would break that functionality. Also, are
>> there any other build settings that need to arrange for the
>> module autoload ?
> 
> I suppose no during my test on board.

So the device is likely triggering the module auto-load
via the helper ? It would be good to fully understand this part,
since it also means that any initramfs needs the module.

What type of boot are you doing for the test ? Is there an
initramfs/initrd involved ?

Bruce

> 
> Thanks,
> Liwei.
> 
> 
>>
>> Since there is that possibility, restating the problem you are
>> trying to fix would be good.
>>
>> Bruce
>>
>>>
>>> Signed-off-by: Liwei Song <liwei.song at windriver.com>
>>> ---
>>>    features/i915/i915.cfg | 2 +-
>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/features/i915/i915.cfg b/features/i915/i915.cfg
>>> index 6dcc60f2dfc7..60cb963e014b 100644
>>> --- a/features/i915/i915.cfg
>>> +++ b/features/i915/i915.cfg
>>> @@ -8,6 +8,6 @@ CONFIG_AGP=y
>>>    CONFIG_AGP_INTEL=y
>>>    CONFIG_DRM=y
>>>    CONFIG_DRM_KMS_HELPER=y
>>> -CONFIG_DRM_I915=y
>>> +CONFIG_DRM_I915=m
>>>    CONFIG_DRM_KMS_FB_HELPER=y
>>>    CONFIG_DRM_I915_ALPHA_SUPPORT=y
>>>
>>
>>
>>