From: Keyon Jie <yang.jie@linux.intel.com> To: Takashi Iwai <tiwai@suse.de> Cc: "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>, Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>, "Rajwa, Marcin" <marcin.rajwa@linux.intel.com> Subject: Re: [alsa-devel] [PATCH] ALSA: pcm: fix buffer_bytes max constrained by preallocated bytes issue Date: Sun, 19 Jan 2020 16:11:17 +0800 Message-ID: <c7a64462-1cc1-234b-ac96-7774e6116118@linux.intel.com> (raw) In-Reply-To: <s5himl7orc4.wl-tiwai@suse.de> On 2020/1/19 下午3:09, Takashi Iwai wrote: > On Sun, 19 Jan 2020 04:52:55 +0100, > Keyon Jie wrote: >> >> >> On 2020/1/17 下午7:12, Takashi Iwai wrote: >>> On Fri, 17 Jan 2020 11:43:24 +0100, >>> Keyon Jie wrote: >>>> >>>> In SOF driver, we don't use kernel config item like >>>> CONFIG_SND_HDA_PREALLOC_SIZE for HDA, the code for it is: >>>> >>>> snd_pcm_lib_preallocate_pages(pcm->streams[stream].substream, >>>> SNDRV_DMA_TYPE_DEV_SG, sdev->dev, >>>> le32_to_cpu(caps->buffer_size_min), >>>> le32_to_cpu(caps->buffer_size_max)); >>>> >>>> So the preallocated size is configured via topology file, that is >>>> caps->buffer_size_min, no chance for PulseAudio to reconfigure it. >>>> >>>> So, it looks like we have to change it to this if we don't change the >>>> ALSA core: >>>> >>>> snd_pcm_lib_preallocate_pages(pcm->streams[stream].substream, >>>> SNDRV_DMA_TYPE_DEV_SG, sdev->dev, >>>> - le32_to_cpu(caps->buffer_size_min), >>>> + le32_to_cpu(caps->buffer_size_max), >>>> le32_to_cpu(caps->buffer_size_max)); >>> >>> Yes, passing buffer_size_min for the preallocation sounds already >>> bad. The default value should be sufficient for usual operations, not >>> the cost-cutting minimum. Otherwise there is no merit of >>> preallocation. >>> >>> Alternatively, we may pass 0 there, indicating no limitation, too. >>> But, this would need a bit other adjustment, e.g. snd_pcm_hardware >>> should have lower buffer_bytes_max. >> >> Thank you Takashi, then let's follow it to pre-allocate with >> caps->buffer_size_max, as we don't specify any limitations in >> snd_pcm_hardware today, we want to leave it configurable to each >> specific topology file for different machines. > > How big is caps->buffer_size_max? Passing the value there means > actually trying to allocate the given size as default, and it'd be a > lot of waste if a too large value (e.g. 32MB) is passed there. It varies for each stream, most of them are 65536 Bytes only, whereas one for Wake-On-Voice might need a > 4 Seconds buffer could be up to about 1~2MBytes, and another one for deep-buffer playback can be up to about 8MBytes. > > I think we can go for passing zero as default, which means skipping > preallocation. In addition, we may add an upper limit of the total Just did an experiment and this works for me, I believe we still need to call snd_pcm_set_managed_buffer() though the preallocation is skipped in this, right? > amount of allocation per card, controlled in pcm_memory.c, for > example. This logic can be applied to the legacy HDA, too. > > This should be relatively easy, and I'll provide the patch in the next > week. OK, that's fine for me also, thank you. ~Keyon > > > Takashi > _______________________________________________ > Alsa-devel mailing list > Alsa-devel@alsa-project.org > https://mailman.alsa-project.org/mailman/listinfo/alsa-devel > _______________________________________________ Alsa-devel mailing list Alsa-devel@alsa-project.org https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
next prev parent reply index Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-01-16 4:53 Keyon Jie 2020-01-16 7:15 ` Takashi Iwai 2020-01-16 9:50 ` Keyon Jie 2020-01-16 10:27 ` Takashi Iwai 2020-01-16 11:25 ` Keyon Jie 2020-01-16 11:50 ` Takashi Iwai 2020-01-16 14:14 ` Jie, Yang 2020-01-16 15:31 ` Jie, Yang 2020-01-16 16:07 ` Takashi Iwai 2020-01-16 16:39 ` Pierre-Louis Bossart 2020-01-16 17:25 ` Rajwa, Marcin 2020-01-16 17:40 ` Pierre-Louis Bossart 2020-01-16 20:37 ` Takashi Iwai 2020-01-17 5:30 ` Keyon Jie 2020-01-17 7:57 ` Takashi Iwai 2020-01-17 10:13 ` Keyon Jie 2020-01-17 10:30 ` Takashi Iwai 2020-01-17 10:56 ` Keyon Jie 2020-01-17 11:15 ` Takashi Iwai 2020-01-17 5:37 ` Keyon Jie 2020-01-17 8:00 ` Takashi Iwai 2020-01-17 10:43 ` Keyon Jie 2020-01-17 11:12 ` Takashi Iwai 2020-01-19 3:52 ` Keyon Jie 2020-01-19 7:09 ` Takashi Iwai 2020-01-19 8:11 ` Keyon Jie [this message] 2020-01-19 9:04 ` Takashi Iwai 2020-01-19 10:14 ` Keyon Jie 2020-01-19 10:43 ` Takashi Iwai 2020-01-20 2:23 ` Keyon Jie 2020-01-16 15:45 ` Takashi Iwai
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