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Check control API protocol version for TLV control

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Check control API protocol version to avoid unnecessary ioctl
access for TLV stuff on the older drivers.
This commit is contained in:
Takashi Iwai 2006-09-17 22:06:46 +02:00
parent f70de1b1cc
commit a7bc1dd80c
1 changed files with 7 additions and 1 deletions
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8
src/control/control_hw.c
View file

@ -40,11 +40,12 @@ const char *_snd_module_control_hw = "";
#ifndef DOC_HIDDEN
#define SNDRV_FILE_CONTROL ALSA_DEVICE_DIRECTORY "controlC%i"
#define SNDRV_CTL_VERSION_MAX SNDRV_PROTOCOL_VERSION(2, 0, 3)
#define SNDRV_CTL_VERSION_MAX SNDRV_PROTOCOL_VERSION(2, 0, 4)
typedef struct {
int card;
int fd;
unsigned int protocol;
} snd_ctl_hw_t;
#endif /* DOC_HIDDEN */
@ -208,6 +209,10 @@ static int snd_ctl_hw_elem_tlv(snd_ctl_t *handle, int op_flag,
snd_ctl_hw_t *hw = handle->private_data;
struct sndrv_ctl_tlv *xtlv;
/* we don't support TLV on protocol ver 2.0.3 or earlier */
if (hw->protocol < SNDRV_PROTOCOL_VERSION(2, 0, 4))
return -ENXIO;
switch (op_flag) {
case -1: inum = SNDRV_CTL_IOCTL_TLV_COMMAND; break;
case 0: inum = SNDRV_CTL_IOCTL_TLV_READ; break;
@ -407,6 +412,7 @@ int snd_ctl_hw_open(snd_ctl_t **handle, const char *name, int card, int mode)
}
hw->card = card;
hw->fd = fd;
hw->protocol = ver;
err = snd_ctl_new(&ctl, SND_CTL_TYPE_HW, name);
if (err < 0) {