[Letux-kernel] [PATCH] pwm: pwm-omap-dmtimer: fix probing problems by returning EPROBE_DEFER

H. Nikolaus Schaller hns at goldelico.com
Tue Jul 31 08:35:26 CEST 2018


> Am 31.07.2018 um 00:56 schrieb David Rivshin <drivshin at awxrd.com>:
> 
> On Sun, 29 Jul 2018 20:19:08 +0200
> "H. Nikolaus Schaller" <hns at goldelico.com> wrote:
> 
>> Hi,
>> 
>>> Am 29.07.2018 um 20:08 schrieb Ladislav Michl <ladis at linux-mips.org>:
>>> 
>>> On Sun, Jul 29, 2018 at 08:32:41AM +0200, H. Nikolaus Schaller wrote:  
>>>> Hi,
>>>> 
>>>>> Am 28.07.2018 um 22:35 schrieb Ladislav Michl <ladis at linux-mips.org>:
>>>>> 
>>>>> Hi Andreas,
>>>>> 
>>>>> On Sat, Jul 28, 2018 at 06:59:14PM +0200, Andreas Kemnade wrote:  
>>>>>> I got this in the kernel log:
>>>>>> [    0.756042] omap-dmtimer-pwm dmtimer-pwm: dmtimer pdata structure NULL
>>>>>> [    0.756134] omap-dmtimer-pwm: probe of dmtimer-pwm failed with error -22
>>>>>> 
>>>>>> the probe function has to wait until omap_dm_timer_probe() in
>>>>>> clocksource/timer-ti-dm.c has initialized pdata, so defer probing  
>>>>> 
>>>>> There already is a patch by David Rivshin addressing the same issue...  
>>>> 
>>>> Here it is:
>>>> 
>>>> https://patchwork.ozlabs.org/patch/943148/
>>>> 
>>>> but hasn't arrived in linux-next.  
>>> 
>>> That's because there'll be v3.
>>> 
>>>> But it is questionable if a driver should dev_info() about doing deferred probing.
>>>> IMHO, it should just do it which is how Andreas' patch works.  
>>> 
>>> See here: https://patchwork.ozlabs.org/patch/949659/  
>> 
>> Ah, I see (neither Andreas nor me did follow the original discussions
>> and therefore came up independently with the same thoughts).
> 
> Seems a lot of us have tripped over this problem at roughly the same 
> time. I'm hoping Thierry picks it up in time for the 4.19 merge window.

Well, if possible it should be backported to 4.18 and 4.17.

> 
>> So we will wait for the v3.
> 
> FYI, v3 has been posted: https://patchwork.ozlabs.org/patch/951299/
> Let me know if you feel strongly enough about having no message
> (vs dev_dbg) for me to spin a quick v4.

I am fine with dev_dbg.

> Seems like each additional 
> pair of eyes leans in that direction.
> 
> Ladislav, I realized just after I sent that I forgot to add your ack
> to the commit message. Sorry for the oversight.
> 

BR and thanks,
Nikolaus



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