linux-kernel - Re: [alsa-devel] [PATCH 08/14] soundwire: Add Slave status handling helpers

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Message-ID: <20171101090820.GA3187@localhost>
Date:   Wed, 1 Nov 2017 14:38:20 +0530
From:   Vinod Koul <vinod.koul@...el.com>
To:     Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
Cc:     Takashi Iwai <tiwai@...e.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        ALSA <alsa-devel@...a-project.org>,
        Charles Keepax <ckeepax@...nsource.cirrus.com>,
        Sudheer Papothi <spapothi@...eaurora.org>, plai@...eaurora.org,
        LKML <linux-kernel@...r.kernel.org>, patches.audio@...el.com,
        Mark <broonie@...nel.org>, srinivas.kandagatla@...aro.org,
        Shreyas NC <shreyas.nc@...el.com>,
        Sanyog Kale <sanyog.r.kale@...el.com>,
        Sagar Dharia <sdharia@...eaurora.org>, alan@...ux.intel.com
Subject: Re: [alsa-devel] [PATCH 08/14] soundwire: Add Slave status handling
 helpers

On Wed, Nov 01, 2017 at 02:49:15AM +0530, Pierre-Louis Bossart wrote:
> 
> >
> >>>+		if (found == false) {
> >>>+			/* TODO: Park this device in Group 13 */
> >>>+			dev_err(bus->dev, "Slave Entry not found");
> >>
> >>No break here?  Otherwise...
> >
> >Thats intentional. We want to still read next device that show up
> >
> >>
> >>>+		}
> >>>+
> >>>+	} while (ret == 0);
> >>
> >>... the outer loop may go endlessly.
> >>This condition doesn't look effective.
> >
> >not really. We cant keep reading successfully. At some point all slaves will
> >ignore and return ENODATA and we exit. Bus errors will also make it exit
> >
> >BUT given that we have seen stuff i am inclined to add a counter, we cant
> >have more than 11 device so that's a sane value to use :)
> 
> Yep. Keep in mind however that there could be theoretical corner cases: if a
> device is enumerated, loses sync and becomes attached again while you deal
> with others, you'd have more than 11 iterations.

Not really as that would be another interrupt and another status report.

-- 
~Vinod