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From: Vitaly Rodionov <vitalyr@opensource.cirrus.com>
To: Takashi Iwai <tiwai@suse.de>
Cc: Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
	<alsa-devel@alsa-project.org>, <patches@opensource.cirrus.com>,
	<linux-kernel@vger.kernel.org>,
	Lucas Tanure <tanureal@opensource.cirrus.com>,
	Stefan Binding <sbinding@opensource.cirrus.com>
Subject: Re: [PATCH v3 13/27] ALSA: hda/cs8409: Dont disable I2C clock between consecutive accesses
Date: Wed, 11 Aug 2021 19:33:07 +0100	[thread overview]
Message-ID: <499860c1-bf6f-969a-a987-3302820b66af@opensource.cirrus.com> (raw)
In-Reply-To: <s5h7dh51thw.wl-tiwai@suse.de>

On 01/08/2021 9:03 am, Takashi Iwai wrote:
> On Fri, 30 Jul 2021 17:18:30 +0200,
> Vitaly Rodionov wrote:
>> From: Lucas Tanure <tanureal@opensource.cirrus.com>
>>
>> Only disable I2C clock 25 ms after not being used.
>>
>> The current implementation enables and disables the I2C clock for each
>> I2C transaction. Each enable/disable call requires two verb transactions.
>> This means each I2C transaction requires a total of four verb transactions
>> to enable and disable the clock.
>> However, if there are multiple consecutive I2C transactions, it is not
>> necessary to enable and disable the clock each time, instead it is more
>> efficient to enable the clock for the first transaction, and disable it
>> after the final transaction, which would improve performance.
>> This is achieved by using a timeout which disables the clock if no request
>> to enable the clock has occurred for 25 ms.
>>
>> Signed-off-by: Lucas Tanure <tanureal@opensource.cirrus.com>
>> Signed-off-by: Vitaly Rodionov <vitalyr@opensource.cirrus.com>
>> Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
>> ---
>>
>> Changes in v2:
>> - Improved delayed work start/cancel implementation, and re-worked commit message
>>   adding more explanation why this was required.
>>
>> Changes in v3:
>> - Cancel the disable timer, but do not wait for any running disable functions to finish.
>>   If the disable timer runs out before cancel, the delayed work thread will be blocked,
>>   waiting for the mutex to become unlocked. This mutex will be locked for the duration of
>>   any i2c transaction, so the disable function will run to completion immediately
>>   afterwards in the scenario. The next enable call will re-enable the clock, regardless.
> This looks almost fine, but just a couple of thoughts:
>
> - cancel_delayed_work_sync() means to it might keep the i2c enabled
>    after that point (just cancel the pending work).
>    Would it cause a inconsistency afterwards?
>
> - A similar procedure is needed for suspend callback to cancel / flush
>    the work.
>    The shutdown is another question, but usually it's fine to without
>    any special handling as long as the resource is kept.

Hi Takashi,

Thank you very much for your comments. It all make sense.

We will make further improvement and submit next version.

Thanks,

Vitaly

>
> thanks,
>
> Takashi



  reply	other threads:[~2021-08-11 19:04 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-30 15:18 [PATCH v3 00/27] ALSA: hda/cirrus: Split generic cirrus HDA codecs and CS8490 bridge into separate modules Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 01/27] ALSA: hda/cirrus: Move CS8409 HDA bridge to separate module Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 02/27] ALSA: hda/cs8409: Move arrays of configuration to a new file Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 03/27] ALSA: hda/cs8409: Use enums for register names and coefficients Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 04/27] ALSA: hda/cs8409: Mask all CS42L42 interrupts on initialization Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 05/27] ALSA: hda/cs8409: Reduce HS pops/clicks for Cyborg Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 06/27] ALSA: hda/cs8409: Disable unnecessary Ring Sense for Cyborg/Warlock/Bullseye Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 07/27] ALSA: hda/cs8409: Disable unsolicited responses during suspend Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 08/27] ALSA: hda/cs8409: Disable unsolicited response for the first boot Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 09/27] ALSA: hda/cs8409: Mask CS42L42 wake events Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 10/27] ALSA: hda/cs8409: Simplify CS42L42 jack detect Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 11/27] ALSA: hda/cs8409: Prevent I2C access during suspend time Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 12/27] ALSA: hda/cs8409: Generalize volume controls Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 13/27] ALSA: hda/cs8409: Dont disable I2C clock between consecutive accesses Vitaly Rodionov
2021-08-01  8:03   ` Takashi Iwai
2021-08-11 18:33     ` Vitaly Rodionov [this message]
2021-07-30 15:18 ` [PATCH v3 14/27] ALSA: hda/cs8409: Avoid setting the same I2C address for every access Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 15/27] ALSA: hda/cs8409: Avoid re-setting the same page as the last access Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 16/27] ALSA: hda/cs8409: Support i2c bulk read/write functions Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 17/27] ALSA: hda/cs8409: Separate CS8409, CS42L42 and project functions Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 18/27] ALSA: hda/cs8409: Move codec properties to its own struct Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 19/27] ALSA: hda/cs8409: Support multiple sub_codecs for Suspend/Resume/Unsol events Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 20/27] ALSA: hda/cs8409: Add Support to disable jack type detection for CS42L42 Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 21/27] ALSA: hda/cs8409: Add support for dolphin Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 22/27] ALSA: hda/cs8409: Enable Full Scale Volume for Line Out Codec on Dolphin Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 23/27] ALSA: hda/cs8409: Set fixed sample rate of 48kHz for CS42L42 Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 24/27] ALSA: hda/cs8409: Use timeout rather than retries for I2C transaction waits Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 25/27] ALSA: hda/cs8409: Remove unnecessary delays Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 26/27] ALSA: hda/cs8409: Follow correct CS42L42 power down sequence for suspend Vitaly Rodionov
2021-07-30 15:18 ` [PATCH v3 27/27] ALSA: hda/cs8409: Unmute/Mute codec when stream starts/stops Vitaly Rodionov

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