2b58fd5b31
Playback Designs' USB devices have some hardware limitations on their USB interface. In particular: - They need a 20ms delay after each class compliant request as the hardware ACKs the USB packets before the device is actually ready for the next command. Sending data immediately will result in buffer overflows in the hardware. - The devices send bogus feedback data at the start of each stream which confuse the feedback format auto-detection. This patch introduces a new quirks hook that is called after each control packet and which adds a delay for all devices that match Playback Designs' USB VID for now. In addition, it adds a counter to snd_usb_endpoint to drop received packets on the floor. Another new quirks function that is called once an endpoint is started initializes that counter for these devices on their sync endpoint. Signed-off-by: Daniel Mack <zonque@gmail.com> Reported-and-tested-by: Andreas Koch <andreas@akdesigninc.com> Supported-by: Demian Martin <demianm_1@yahoo.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
124 lines
2.9 KiB
C
124 lines
2.9 KiB
C
/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/usb.h>
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#include "usbaudio.h"
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#include "helper.h"
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#include "quirks.h"
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/*
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* combine bytes and get an integer value
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*/
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unsigned int snd_usb_combine_bytes(unsigned char *bytes, int size)
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{
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switch (size) {
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case 1: return *bytes;
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case 2: return combine_word(bytes);
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case 3: return combine_triple(bytes);
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case 4: return combine_quad(bytes);
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default: return 0;
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}
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}
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/*
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* parse descriptor buffer and return the pointer starting the given
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* descriptor type.
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*/
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void *snd_usb_find_desc(void *descstart, int desclen, void *after, u8 dtype)
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{
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u8 *p, *end, *next;
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p = descstart;
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end = p + desclen;
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for (; p < end;) {
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if (p[0] < 2)
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return NULL;
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next = p + p[0];
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if (next > end)
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return NULL;
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if (p[1] == dtype && (!after || (void *)p > after)) {
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return p;
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}
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p = next;
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}
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return NULL;
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}
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/*
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* find a class-specified interface descriptor with the given subtype.
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*/
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void *snd_usb_find_csint_desc(void *buffer, int buflen, void *after, u8 dsubtype)
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{
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unsigned char *p = after;
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while ((p = snd_usb_find_desc(buffer, buflen, p,
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USB_DT_CS_INTERFACE)) != NULL) {
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if (p[0] >= 3 && p[2] == dsubtype)
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return p;
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}
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return NULL;
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}
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/*
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* Wrapper for usb_control_msg().
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* Allocates a temp buffer to prevent dmaing from/to the stack.
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*/
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int snd_usb_ctl_msg(struct usb_device *dev, unsigned int pipe, __u8 request,
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__u8 requesttype, __u16 value, __u16 index, void *data,
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__u16 size)
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{
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int err;
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void *buf = NULL;
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if (size > 0) {
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buf = kmemdup(data, size, GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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}
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err = usb_control_msg(dev, pipe, request, requesttype,
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value, index, buf, size, 1000);
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if (size > 0) {
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memcpy(data, buf, size);
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kfree(buf);
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}
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snd_usb_ctl_msg_quirk(dev, pipe, request, requesttype,
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value, index, data, size);
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return err;
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}
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unsigned char snd_usb_parse_datainterval(struct snd_usb_audio *chip,
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struct usb_host_interface *alts)
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{
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switch (snd_usb_get_speed(chip->dev)) {
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case USB_SPEED_HIGH:
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case USB_SPEED_SUPER:
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if (get_endpoint(alts, 0)->bInterval >= 1 &&
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get_endpoint(alts, 0)->bInterval <= 4)
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return get_endpoint(alts, 0)->bInterval - 1;
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break;
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default:
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break;
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}
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return 0;
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}
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