From: Takashi Iwai <tiwai@suse.de>
To: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc: patches.audio@intel.com, alsa-devel@alsa-project.org,
broonie@kernel.org,
"Subhransu S. Prusty" <subhransu.s.prusty@intel.com>,
lgirdwood@gmail.com
Subject: Re: [PATCH 7/7] ALSA: usb: take startup delay into account
Date: Fri, 21 Oct 2016 18:00:20 +0200 [thread overview]
Message-ID: <s5hd1itg0a3.wl-tiwai@suse.de> (raw)
In-Reply-To: <efce9dd9-b3f3-b7cf-86df-c6be4e0014cd@linux.intel.com>
On Mon, 03 Oct 2016 17:04:23 +0200,
Pierre-Louis Bossart wrote:
>
>
> >> For playback usages, the endpoints are started before the prepare
> >> step, and valid audio data will be rendered with a delay that
> >> cannot be recovered.
> >> Worst-case the initial delay due to buffering of empty URBS can
> >> be up to 12ms
>
> > This is really a fix unlike other patches in the series.
> > Please split it from others, so that we can apply it easily.
>
> There was also additional discussions on this topic since I put this
> together, not sure it makes sense to merge this patch at the moment.
> In the Windows driver, the URBs can be submitted at a specific time,
> which allows for synchronous starts of all endpoints (limited to the
> 1ms frame resolution). In Linux we can't since the start time is owned
> by the xhci driver and can't be modified by the class driver. I talked
> with Mathias Nyman and Baolu Lu on this before the summer and of
> course I became busy with other things. The short story is that there
> is a wider problem with USB start and linking endpoints that should be
> addressed as a single step. Maybe something to talk about at the
> miniconference?
Sure, why not. Now it's close to LPC and we won't reach to the
solution soonish yet.
Takashi
next prev parent reply other threads:[~2016-10-21 16:00 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-30 12:43 [PATCH 0/7] ALSA: Add rewinds disabled, delays, max_inflight_bytes Subhransu S. Prusty
2016-09-30 12:43 ` [PATCH 1/7] ALSA: core: let low-level driver or userspace disable rewinds Subhransu S. Prusty
2016-09-30 13:22 ` Takashi Iwai
2016-10-03 4:40 ` Subhransu S. Prusty
2016-10-03 14:39 ` Pierre-Louis Bossart
2016-10-21 15:57 ` Takashi Iwai
2016-09-30 12:43 ` [PATCH 2/7] ALSA: core: add .update_appl_ptr callback for pcm ops Subhransu S. Prusty
2016-09-30 13:24 ` Takashi Iwai
2016-09-30 17:20 ` Vinod Koul
2016-09-30 18:38 ` Takashi Iwai
2016-10-03 4:36 ` Vinod Koul
2016-10-03 14:49 ` Pierre-Louis Bossart
2016-09-30 12:43 ` [PATCH 3/7] ALSA: pcm: avoid mmap of control data if .update_appl_ptr is implemented Subhransu S. Prusty
2016-09-30 13:40 ` Takashi Iwai
2016-10-03 4:43 ` Subhransu S. Prusty
2016-09-30 12:43 ` [PATCH 4/7] ALSA: core: add report of max inflight bytes Subhransu S. Prusty
2016-09-30 13:44 ` Takashi Iwai
2016-09-30 12:43 ` [PATCH 5/7] ALSA: hda: add default value for max_inflight_bytes Subhransu S. Prusty
2016-10-03 8:48 ` Hardik Shah
2016-10-03 14:44 ` Pierre-Louis Bossart
2016-09-30 12:43 ` [PATCH 6/7] ALSA: usb: no_period_wake and max_inflight_bytes report Subhransu S. Prusty
2016-09-30 12:43 ` [PATCH 7/7] ALSA: usb: take startup delay into account Subhransu S. Prusty
2016-09-30 13:44 ` Takashi Iwai
2016-10-03 15:04 ` Pierre-Louis Bossart
2016-10-21 16:00 ` Takashi Iwai [this message]
2016-10-03 6:46 ` Takashi Sakamoto
2016-10-03 15:08 ` Pierre-Louis Bossart
2016-10-03 17:31 ` Takashi Sakamoto
2016-09-30 13:13 ` [PATCH 0/7] ALSA: Add rewinds disabled, delays, max_inflight_bytes Takashi Iwai
2016-10-03 4:28 ` Subhransu S. Prusty
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