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From: Clemens Ladisch <clemens@ladisch.de>
To: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Cc: alsa-devel@alsa-project.org, ffado-devel@lists.sf.net
Subject: Re: [PATCH 11/39] firewire-lib: Add support for channel mapping
Date: Tue, 11 Mar 2014 09:23:19 +0100	[thread overview]
Message-ID: <531EC7F7.7030405@ladisch.de> (raw)
In-Reply-To: <531DB002.9030801@sakamocchi.jp>

Takashi Sakamoto wrote:
> (Mar 10 2014 06:20), Clemens Ladisch wrote:
>> This change is not necessary.  I used a separate local variable
>> deliberately to allow the compiler to recognize that it cannot be
>> aliased with the buffer contents.
>
> I cannot understand your intention.

In code like this:

        for (... s->channels ...)
            buffer[i] = ...;

it is, as far as the compiler knows, possible that &buffer[i] and
&s->channels actually point to the same variable, so s->channels must
be reloaded in every loop iteration.  A local variable avoids that.

(Whether this optimization is worth it is another question ...)

>> AFAICS the dual-wire format could be handled easier by setting pcm_positions[]
>> in the dice driver.
>
> Currently I have no interests of dice driver.

Okay, I'll write a patch on top of that.


Regards,
Clemens

  parent reply	other threads:[~2014-03-11  8:23 UTC|newest]

Thread overview: 76+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <5316963F.1000206@sakamocchi.jp>
2014-03-05  6:14 ` [GIT PULL v2] Enhancement of support for Firewire devices Takashi Iwai
2014-03-05 11:00   ` Takashi Sakamoto
2014-03-05 11:09     ` Takashi Iwai
2014-03-05 11:23       ` Takashi Sakamoto
2014-03-05 10:47 ` [GIT PULL][PATCH 00/39 " Takashi Sakamoto
2014-03-05 10:47   ` [PATCH 01/39] firewire-lib: Rename functions, structure, member for AMDTP Takashi Sakamoto
2014-03-05 10:47   ` [PATCH 02/39] firewire-lib: Add macros instead of fixed value " Takashi Sakamoto
2014-03-05 10:47   ` [PATCH 03/39] firewire-lib: Add 'direction' member to 'amdtp_stream' structure Takashi Sakamoto
2014-03-05 10:47   ` [PATCH 04/39] firewire-lib: Split some codes into functions to reuse for both streams Takashi Sakamoto
2014-03-05 10:47   ` [PATCH 05/39] firewire-lib: Add support for AMDTP in-stream and PCM capture Takashi Sakamoto
2014-03-09 20:37     ` Clemens Ladisch
2014-03-10  3:55       ` Takashi Sakamoto
2014-03-12  2:00       ` Takashi Sakamoto
2014-03-14 13:50       ` Takashi Sakamoto
2014-03-05 10:47   ` [PATCH 06/39] firewire-lib: Add support for MIDI capture/playback Takashi Sakamoto
2014-03-09 20:48     ` Clemens Ladisch
2014-03-10  4:13       ` Takashi Sakamoto
2014-03-05 10:47   ` [PATCH 07/39] firewire-lib: Give syt value as parameter to handle_out_packet() Takashi Sakamoto
2014-03-05 10:47   ` [PATCH 08/39] firewire-lib: Add support for duplex streams synchronization in blocking mode Takashi Sakamoto
2014-03-09 20:55     ` Clemens Ladisch
2014-03-10 12:21       ` Takashi Sakamoto
2014-03-05 10:47   ` [PATCH 09/39] firewire-lib: Add sort function for transmitted packet Takashi Sakamoto
2014-03-09 21:07     ` Clemens Ladisch
2014-03-10 13:29       ` Takashi Sakamoto
2014-03-11  8:11         ` Clemens Ladisch
2014-03-12  1:23           ` Takashi Sakamoto
2014-03-12  7:21             ` Takashi Iwai
2014-03-05 10:47   ` [PATCH 10/39] firewire-lib: Add transfer delay to synchronized duplex streams Takashi Sakamoto
2014-03-09 21:13     ` Clemens Ladisch
2014-03-10 13:43       ` Takashi Sakamoto
2014-03-11  8:13         ` Clemens Ladisch
2014-03-05 10:47   ` [PATCH 11/39] firewire-lib: Add support for channel mapping Takashi Sakamoto
2014-03-09 21:20     ` Clemens Ladisch
2014-03-10 12:28       ` Takashi Sakamoto
2014-03-10 12:58         ` Takashi Sakamoto
2014-03-11  8:23         ` Clemens Ladisch [this message]
2014-03-11 16:03           ` Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 12/39] firewire-lib: Rename macros, variables and functions for CMP Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 13/39] firewire-lib: Add 'direction' member to 'cmp_connection' structure Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 14/39] firewire-lib: Add handling output connection by CMP Takashi Sakamoto
2014-03-09 21:27     ` Clemens Ladisch
2014-03-10 12:30       ` Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 15/39] firewire-lib: Add a new function to check others' connection Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 16/39] firewire-lib: Add some AV/C general commands Takashi Sakamoto
2014-03-09 21:32     ` Clemens Ladisch
2014-03-10 12:46       ` Takashi Sakamoto
2014-03-14 14:10       ` Takashi Sakamoto
2014-03-14 22:18         ` Clemens Ladisch
2014-03-05 10:48   ` [PATCH 17/39] firewire-lib: Add quirks for Fireworks Takashi Sakamoto
2014-03-09 21:39     ` Clemens Ladisch
2014-03-10 12:40       ` Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 18/39] firewire-lib: Add a fallback at RCODE_CANCELLED Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 19/39] fireworks: Add skelton for Fireworks based devices Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 20/39] fireworks: Add transaction and some commands Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 21/39] fireworks: Add connection and stream management Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 22/39] fireworks: Add proc interface for debugging purpose Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 23/39] fireworks: Add MIDI interface Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 24/39] fireworks: Add PCM interface Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 25/39] fireworks: Add hwdep interface Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 26/39] fireworks: Add command/response functionality into " Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 27/39] bebob: Add skelton for BeBoB based devices Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 28/39] bebob: Add commands and connections/streams management Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 29/39] bebob: Add proc interface for debugging purpose Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 30/39] bebob: Add MIDI interface Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 31/39] bebob: Add PCM interface Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 32/39] bebob: Add hwdep interface Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 33/39] bebob: Prepare for device specific operations Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 34/39] bebob: Add support for Terratec PHASE, EWS series and Aureon Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 35/39] bebob: Add support for Yamaha GO series Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 36/39] bebob: Add support for Focusrite Saffire/SaffirePro series Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 37/39] bebob: Add support for M-Audio usual Firewire series Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 38/39] bebob: Add support for M-Audio special " Takashi Sakamoto
2014-03-05 10:48   ` [PATCH 39/39] bebob: Send a cue to load firmware for M-Audio " Takashi Sakamoto
2014-03-07 11:44 ` [GIT PULL v2] Enhancement of support for Firewire devices Takashi Iwai
2014-03-07 14:46   ` Clemens Ladisch
2014-02-28  3:27 [GIT PULL][PATCH 00/39] " Takashi Sakamoto
2014-02-28  3:27 ` [PATCH 11/39] firewire-lib: Add support for channel mapping Takashi Sakamoto

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