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ALSA: usb-audio: Simplify with usb_endpoint_max_periodic_payload() 

Recently we received a new helper function,
usb_endpoint_max_periodic_payload(), for calculating the max packet
size for periodic transfer.

Simplify the former open code with the new helper function.

Fixes: a748e1dbb2 ("ALSA: usb-audio: Fix max bytes-per-interval calculation")
Suggested-by: Michal Pecio <michal.pecio@gmail.com>
Link: https://lore.kernel.org/20251124210518.90054-1-dylan_robinson@motu.com
Link: https://patch.msgid.link/20251202070828.145656-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
pull/1354/merge
Takashi Iwai 2025-12-02 08:08:27 +01:00
parent a30fa81222
commit cf5425e207
1 changed files with 2 additions and 32 deletions
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34
sound/usb/stream.c
View File

@ -684,43 +684,13 @@ snd_usb_find_output_terminal_descriptor(struct usb_host_interface *ctrl_iface,
return NULL;
}
static unsigned int
snd_usb_max_bytes_per_interval(struct snd_usb_audio *chip,
struct usb_host_interface *alts)
{
struct usb_host_endpoint *ep = &alts->endpoint[0];
unsigned int max_bytes = usb_endpoint_maxp(&ep->desc);
/* SuperSpeed isoc endpoints have up to 16 bursts of up to 3 packets each */
if (snd_usb_get_speed(chip->dev) >= USB_SPEED_SUPER) {
int burst = 1 + ep->ss_ep_comp.bMaxBurst;
int mult = USB_SS_MULT(ep->ss_ep_comp.bmAttributes);
max_bytes *= burst;
max_bytes *= mult;
}
if (snd_usb_get_speed(chip->dev) == USB_SPEED_SUPER_PLUS &&
USB_SS_SSP_ISOC_COMP(ep->ss_ep_comp.bmAttributes)) {
max_bytes = le32_to_cpu(ep->ssp_isoc_ep_comp.dwBytesPerInterval);
}
/* High speed, 1-3 packets/uframe, max 6 for eUSB2 double bw */
if (snd_usb_get_speed(chip->dev) == USB_SPEED_HIGH) {
if (usb_endpoint_is_hs_isoc_double(chip->dev, ep))
max_bytes = le32_to_cpu(ep->eusb2_isoc_ep_comp.dwBytesPerInterval);
else
max_bytes *= usb_endpoint_maxp_mult(&ep->desc);
}
return max_bytes;
}
static struct audioformat *
audio_format_alloc_init(struct snd_usb_audio *chip,
struct usb_host_interface *alts,
int protocol, int iface_no, int altset_idx,
int altno, int num_channels, int clock)
{
struct usb_host_endpoint *ep = &alts->endpoint[0];
struct audioformat *fp;
fp = kzalloc(sizeof(*fp), GFP_KERNEL);
@ -734,7 +704,7 @@ audio_format_alloc_init(struct snd_usb_audio *chip,
fp->ep_attr = get_endpoint(alts, 0)->bmAttributes;
fp->datainterval = snd_usb_parse_datainterval(chip, alts);
fp->protocol = protocol;
fp->maxpacksize = snd_usb_max_bytes_per_interval(chip, alts);
fp->maxpacksize = usb_endpoint_max_periodic_payload(chip->dev, ep);
fp->channels = num_channels;
fp->clock = clock;
INIT_LIST_HEAD(&fp->list);