linux-kernel - Re: [PATCH] irqdomain: provide useful debugging information for irq domain

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Date:   Thu, 18 Jan 2018 08:54:07 +0000
From:   Marc Zyngier <marc.zyngier@....com>
To:     "Yang, Shunyong" <shunyong.yang@...-semitech.com>,
        "tglx@...utronix.de" <tglx@...utronix.de>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Zheng, Joey" <yu.zheng@...-semitech.com>
Subject: Re: [PATCH] irqdomain: provide useful debugging information for irq
 domain

On 18/01/18 01:53, Yang, Shunyong wrote:
> Hi, Marc
> 
> On Wed, 2018-01-17 at 10:43 +0000, Marc Zyngier wrote:
>> On 17/01/18 10:20, Yang, Shunyong wrote:
>>>
>>> Hi, Thomas and Marc,
>>>
>>> On Wed, 2018-01-17 at 11:01 +0100, Thomas Gleixner wrote:
>>>>
>>>> On Wed, 17 Jan 2018, Yang, Shunyong wrote:
>>>>>
>>>>>
>>>>> On Wed, 2018-01-17 at 10:33 +0100, Thomas Gleixner wrote:
>>>>>>
>>>>>>
>>>>>> And how is that different from:
>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> The nodes under debugfs irq/irqs describes information of
>>>>>>> every
>>>>>>> single
>>>>>>> irq.
>>>>>> Not at all. It contains the complete hierarchical information
>>>>>> of
>>>>>> each
>>>>>> virq.
>>>>>>
>>>>> I think irq_domain_mapping can provide some high-level
>>>>> information
>>>>> in a
>>>>> summary style.
>>>>> For example, we can check all the IRQs connect to a specific
>>>>> irq
>>>>> chip
>>>>> or irq domain.
>>>> You can retrieve the same information from the irq/irqs files.
>>>> All it
>>>> takes
>>>> is a shell script.
>>>>
>>>> Aside of that with hierarchical irq domains the old debug output
>>>> is
>>>> just
>>>> useless.
>>>>
>>> Umm...Agree. Need I post a patch to remove it?
>> I'm on it.
>>
> In addition to the "%p" to "%px" change in IRQ_DOMAIN_DEBUG you have
> posted patch to remove it, my original patch includes several other
> changes:
> 1. change to "%px" in kasprintf() parameters in
> function __irq_domain_alloc_fwnode() to build name which reflects the
> real pointer address from caller, this may be useful when reading debug
> information.
>  
> n = kasprintf(GFP_KERNEL, "irqchip@%px", data);

Have you investigated whether %pK would work in a debug context?

> 
> 2. other 3 changes from "%p" to "%px" in existing pr_debug().
> 
> Could I submit a V2 patch which depends on your "irqdomain: Kill
> CONFIG_IRQ_DOMAIN_DEBUG" patch to handle this? 
> Following is the link of your patch,
> https://patchwork.kernel.org/patch/10169367/ 

Sure. If you think something is missing, feel free to send an additional
patch.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...