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From: Miquel Raynal <miquel.raynal@bootlin.com>
To: "Zbigniew, Lukwinski" <zbigniew.lukwinski@linux.intel.com>
Cc: Frank Li <Frank.Li@nxp.com>,
	alexandre.belloni@bootlin.com, conor.culhane@silvaco.com,
	imx@lists.linux.dev, joe@perches.com,
	linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/6] i3c: master: add enable(disable) hot join in sys entry
Date: Fri, 20 Oct 2023 15:45:28 +0200	[thread overview]
Message-ID: <20231020154528.2f5f68f5@xps-13> (raw)
In-Reply-To: <57efe6de-cf65-32ed-fd1e-a388e1676c70@linux.intel.com>

Hi Lukwinski,

zbigniew.lukwinski@linux.intel.com wrote on Fri, 20 Oct 2023 10:55:27
+0200:

> On 10/18/2023 10:59 PM, Frank Li wrote:
> > Add hotjoin entry in sys file system allow user enable/disable hotjoin
> > feature.
> >
> > Add (*enable(disable)_hotjoin)() to i3c_master_controller_ops.
> > Add api i3c_master_enable(disable)_hotjoin();  
> 
> What is the use case for having HJ enable knob in sysfs available for user space other than for debug stuff? In other words, does user space really need to enable/disable HJ in runtime for other reason but debug? If it is only for debug maybe it  could be move to debugFS?

I don't think hotjoin should be considered as a debug feature. The
problem here is the power consumption which is higher if you enable
this feature (you need to keep everything clocked and ready to handle
an IBI) whereas if your design is "fixed" (more like an I2C bus) you
may save power by disabling this feature.

A module parameter does not fit here because it's a per-bus
configuration.

Thanks,
Miquèl

WARNING: multiple messages have this Message-ID (diff)
From: Miquel Raynal <miquel.raynal@bootlin.com>
To: "Zbigniew, Lukwinski" <zbigniew.lukwinski@linux.intel.com>
Cc: Frank Li <Frank.Li@nxp.com>,
	alexandre.belloni@bootlin.com, conor.culhane@silvaco.com,
	imx@lists.linux.dev, joe@perches.com,
	linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/6] i3c: master: add enable(disable) hot join in sys entry
Date: Fri, 20 Oct 2023 15:45:28 +0200	[thread overview]
Message-ID: <20231020154528.2f5f68f5@xps-13> (raw)
In-Reply-To: <57efe6de-cf65-32ed-fd1e-a388e1676c70@linux.intel.com>

Hi Lukwinski,

zbigniew.lukwinski@linux.intel.com wrote on Fri, 20 Oct 2023 10:55:27
+0200:

> On 10/18/2023 10:59 PM, Frank Li wrote:
> > Add hotjoin entry in sys file system allow user enable/disable hotjoin
> > feature.
> >
> > Add (*enable(disable)_hotjoin)() to i3c_master_controller_ops.
> > Add api i3c_master_enable(disable)_hotjoin();  
> 
> What is the use case for having HJ enable knob in sysfs available for user space other than for debug stuff? In other words, does user space really need to enable/disable HJ in runtime for other reason but debug? If it is only for debug maybe it  could be move to debugFS?

I don't think hotjoin should be considered as a debug feature. The
problem here is the power consumption which is higher if you enable
this feature (you need to keep everything clocked and ready to handle
an IBI) whereas if your design is "fixed" (more like an I2C bus) you
may save power by disabling this feature.

A module parameter does not fit here because it's a per-bus
configuration.

Thanks,
Miquèl

-- 
linux-i3c mailing list
linux-i3c@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-i3c

  reply	other threads:[~2023-10-20 13:57 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-18 20:59 [PATCH v2 0/6] i3c: master: some improvment for i3c master Frank Li
2023-10-18 20:59 ` Frank Li
2023-10-18 20:59 ` [PATCH v2 1/6] i3c: master: add enable(disable) hot join in sys entry Frank Li
2023-10-18 20:59   ` Frank Li
2023-10-20  8:55   ` Zbigniew, Lukwinski
2023-10-20  8:55     ` Zbigniew, Lukwinski
2023-10-20 13:45     ` Miquel Raynal [this message]
2023-10-20 13:45       ` Miquel Raynal
2023-10-20 14:20       ` Frank Li
2023-10-20 14:20         ` Frank Li
2023-10-20 14:33         ` Miquel Raynal
2023-10-20 14:33           ` Miquel Raynal
2023-10-20 16:24           ` Frank Li
2023-10-20 16:24             ` Frank Li
     [not found]           ` <8a7ac52e-f102-6f5e-35ab-217e6ecc6ba5@linux.intel.com>
2023-10-20 20:25             ` Alexandre Belloni
2023-10-20 20:25               ` Alexandre Belloni
2023-10-20 20:36               ` Frank Li
2023-10-20 20:36                 ` Frank Li
2023-10-20 20:42                 ` Zbigniew, Lukwinski
2023-10-20 20:42                   ` Zbigniew, Lukwinski
2023-11-05 15:36                   ` Frank Li
2023-11-05 15:36                     ` Frank Li
2023-10-18 20:59 ` [PATCH v2 2/6] i3c: master: svc: add hot join support Frank Li
2023-10-18 20:59   ` Frank Li
2023-10-18 20:59 ` [PATCH v2 3/6] i3c: add actual_len in i3c_priv_xfer Frank Li
2023-10-18 20:59   ` Frank Li
2023-10-18 20:59 ` [PATCH v2 4/6] i3c: svc: rename read_len as actual_len Frank Li
2023-10-18 20:59   ` Frank Li
2023-10-18 20:59 ` [PATCH v2 5/6] i3c: master: svc return actual transfer data len Frank Li
2023-10-18 20:59   ` Frank Li
2023-10-18 20:59 ` [PATCH v2 6/6] i3c: add API i3c_dev_gettstatus_format1() to get target device status Frank Li
2023-10-18 20:59   ` Frank Li
2023-10-18 22:58 [PATCH v2 2/6] i3c: master: svc: add hot join support kernel test robot
2023-10-19  1:23 ` kernel test robot
2023-10-19  1:23 ` kernel test robot

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