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author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-05-20 18:41:44 +0200 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-05-20 18:41:44 +0200 |
commit | 7f06a8b26aba1dc03b42272dc0089a800372c575 (patch) | |
tree | 7c67198f83d069eb13fd417e022d111b7e4c82a1 /Documentation/DocBook | |
parent | Merge branch 'for-linus/i2c-2635' of git://git.fluff.org/bjdooks/linux (diff) | |
parent | Merge branch 'topic/asoc' into for-linus (diff) | |
download | linux-7f06a8b26aba1dc03b42272dc0089a800372c575.tar.xz linux-7f06a8b26aba1dc03b42272dc0089a800372c575.zip |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6: (250 commits)
ALSA: hda: Storage class should be before const qualifier
ASoC: tpa6130a2: Remove CPVSS and HPVdd supplies
ASoC: tpa6130a2: Define output pins with SND_SOC_DAPM_OUTPUT
ASoC: sdp4430 - add sdp4430 pcm ops to DAI.
ASoC: TWL6040: Enable earphone path in codec
ASoC: SDP4430: Add support for Earphone speaker
ASoC: SDP4430: Add sdp4430 machine driver
ASoC: tlv320dac33: Avoid powering off while in BIAS_OFF
ASoC: tlv320dac33: Use dev_dbg in dac33_hard_power function
ALSA: sound/pci/asihpi: Use kzalloc
ALSA: hdmi - dont fail on extra nodes
ALSA: intelhdmi - add id for the CougarPoint chipset
ALSA: intelhdmi - user friendly codec name
ALSA: intelhdmi - add dependency on SND_DYNAMIC_MINORS
ALSA: asihpi: incorrect range check
ALSA: asihpi: testing the wrong variable
ALSA: es1688: add pedantic range checks
ARM: McBSP: Add support for omap4 in McBSP driver
ARM: McBSP: Fix request for irq in OMAP4
OMAP: McBSP: Add 32-bit mode support
...
Diffstat (limited to 'Documentation/DocBook')
-rw-r--r-- | Documentation/DocBook/writing-an-alsa-driver.tmpl | 27 |
1 files changed, 17 insertions, 10 deletions
diff --git a/Documentation/DocBook/writing-an-alsa-driver.tmpl b/Documentation/DocBook/writing-an-alsa-driver.tmpl index 0d0f7b4d4b1a..0ba149de2608 100644 --- a/Documentation/DocBook/writing-an-alsa-driver.tmpl +++ b/Documentation/DocBook/writing-an-alsa-driver.tmpl @@ -5518,34 +5518,41 @@ struct _snd_pcm_runtime { ]]> </programlisting> </informalexample> + + For the raw data, <structfield>size</structfield> field must be + set properly. This specifies the maximum size of the proc file access. </para> <para> - The callback is much more complicated than the text-file - version. You need to use a low-level I/O functions such as + The read/write callbacks of raw mode are more direct than the text mode. + You need to use a low-level I/O functions such as <function>copy_from/to_user()</function> to transfer the data. <informalexample> <programlisting> <![CDATA[ - static long my_file_io_read(struct snd_info_entry *entry, + static ssize_t my_file_io_read(struct snd_info_entry *entry, void *file_private_data, struct file *file, char *buf, - unsigned long count, - unsigned long pos) + size_t count, + loff_t pos) { - long size = count; - if (pos + size > local_max_size) - size = local_max_size - pos; - if (copy_to_user(buf, local_data + pos, size)) + if (copy_to_user(buf, local_data + pos, count)) return -EFAULT; - return size; + return count; } ]]> </programlisting> </informalexample> + + If the size of the info entry has been set up properly, + <structfield>count</structfield> and <structfield>pos</structfield> are + guaranteed to fit within 0 and the given size. + You don't have to check the range in the callbacks unless any + other condition is required. + </para> </chapter> |