Re: [alsa-devel] [PATCH v2 3/5] ASoC: generic-dmaengine-pcm: Prepare formats mask for valid physical sample sizes
From: Lars-Peter Clausen
Date: Wed Jul 02 2014 - 10:14:09 EST
On 07/02/2014 04:12 PM, Takashi Iwai wrote:
At Wed, 02 Jul 2014 16:10:09 +0200,
Lars-Peter Clausen wrote:
On 07/02/2014 03:47 PM, Takashi Iwai wrote:
[...]
+ /*
+ * Prepare formats mask for valid/allowed sample types. If the dma does
+ * not have support for the given physical word size, it needs to be
+ * masked out so user space can not use the format which produces
+ * corrupted audio.
+ * In case the dma driver does not implement the slave_caps the default
+ * assumption is that it supports 1, 2 and 4 bytes widths.
+ */
+ for (i = 0; i <= SNDRV_PCM_FORMAT_LAST; i++) {
+ int bits = snd_pcm_format_physical_width(i);
Better to add a negative value check. Some formats return -EINVAL.
So what should we do with those formats? Not support them?
Yes, these are special formats that can't be handled generically.
Looking through the list in pcm_misc.c there are also some formats where the
physical width is not a multiple of 8. We should probably also skip those.
- Lars
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