linux-kernel - Re: [PATCH 08/15] genirq: Add runtime power management support for IRQ chips

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Message-ID: <56EAD140.3090709@nvidia.com>
Date:	Thu, 17 Mar 2016 15:46:08 +0000
From:	Jon Hunter <jonathanh@...dia.com>
To:	Thomas Gleixner <tglx@...utronix.de>,
	Linus Walleij <linus.walleij@...aro.org>
CC:	Jason Cooper <jason@...edaemon.net>,
	Marc Zyngier <marc.zyngier@....com>,
	Benoît Cousson <bcousson@...libre.com>,
	Tony Lindgren <tony@...mide.com>,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	"Stephen Warren" <swarren@...dotorg.org>,
	Thierry Reding <thierry.reding@...il.com>,
	Kevin Hilman <khilman@...nel.org>,
	Geert Uytterhoeven <geert@...ux-m68k.org>,
	Grygorii Strashko <grygorii.strashko@...com>,
	Lars-Peter Clausen <lars@...afoo.de>,
	<linux-tegra@...r.kernel.org>, <linux-omap@...r.kernel.org>,
	<devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 08/15] genirq: Add runtime power management support for
 IRQ chips


On 17/03/16 15:02, Thomas Gleixner wrote:
> On Thu, 17 Mar 2016, Jon Hunter wrote:
>>  /**
>>   * struct irq_chip - hardware interrupt chip descriptor
>>   *
>> + * @parent:		pointer to associated device
> 
> That's really a bad name. parent suggests that this is a parent interrupt chip
> and your explanation sucks as well. What's an associated device? Network card? 

Linus, can you re-iterate your concerns here about just using 'dev' for
the name?

>>  #include <linux/irqdesc.h>
>>  #include <linux/kernel_stat.h>
>> +#include <linux/pm_runtime.h>
>>  
>>  #ifdef CONFIG_SPARSE_IRQ
>>  # define IRQ_BITMAP_BITS	(NR_IRQS + 8196)
>> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
>> index b2a93a37f772..65878e7c7c82 100644
>> --- a/kernel/irq/manage.c
>> +++ b/kernel/irq/manage.c
>> @@ -1114,6 +1114,10 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
>>  	if (!try_module_get(desc->owner))
>>  		return -ENODEV;
>>  
>> +	ret = irq_chip_pm_get(&desc->irq_data);
>> +	if (ret < 0)
>> +		goto out_mput;
> 
> So this call nests inside the chip_bus_lock() region. Is that intentional?

Hmm ... I was trying to simplify the call paths, but yes I think it
would be safer to move outside. Ok, will fix that.

Cheers
Jon