urb completion callback is executed in either host controllers
interrupt context or a tasklet (if hcd has set HCD_BH flag).
If hcd is calling urb->complete from interrupt context, to keep
preempt disable time short, add urbs to a list on completion and
schedule a tasklet to process the list.
Moreover, save timestamp and sof number in the urb completion callback
to avoid any delays.
Signed-off-by: Mian Yousaf Kaukab <yousaf.kau...@intel.com>
---
[Rename from media: uvcvideo: handle urb completion in a work queue]
History:
v2:
- Change to use tasklet instead of workqueue
- Don't use local tasklet if hcd is aleady using tasklet for
completion callback
v1:
- Use global work queue instead of creating ordered queue.
- Add completed urbs to a list and process all on the list when work
is scheduled
- Save timestamp and sof number in urb completion callback and use
in uvc_video_clock_decode() and uvc_video_decode_start()
- Fix race between usb_submit_urb() from uvc_video_complete() and
usb_kill_urb() from uvc_uninit_video()
drivers/media/usb/uvc/uvc_driver.c | 8 +++
drivers/media/usb/uvc/uvc_isight.c | 3 +-
drivers/media/usb/uvc/uvc_video.c | 144 ++++++++++++++++++++++++++++---------
drivers/media/usb/uvc/uvcvideo.h | 18 ++++-
4 files changed, 134 insertions(+), 39 deletions(-)
diff --git a/drivers/media/usb/uvc/uvc_driver.c
b/drivers/media/usb/uvc/uvc_driver.c
index 4b5b3e8..218d4f5 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -21,6 +21,7 @@
#include <linux/vmalloc.h>
#include <linux/wait.h>
#include <linux/version.h>
+#include <linux/usb/hcd.h>
#include <asm/unaligned.h>
#include <media/v4l2-common.h>
@@ -1945,6 +1946,13 @@ static int uvc_probe(struct usb_interface *intf,
"supported.\n", ret);
}
+ /*
+ * This shouldn't be here. But since not all hcd are using tasklet for
+ * urb completion callback, Check this from hcd and only use tasklet
+ * for handling urb completion if hcd is not already using it.
+ */
+ dev->hcd_uses_bh = hcd_giveback_urb_in_bh(bus_to_hcd(udev->bus));
+
uvc_trace(UVC_TRACE_PROBE, "UVC device initialized.\n");
usb_enable_autosuspend(udev);
return 0;
diff --git a/drivers/media/usb/uvc/uvc_isight.c
b/drivers/media/usb/uvc/uvc_isight.c
index 8510e725..7f93d09 100644
--- a/drivers/media/usb/uvc/uvc_isight.c
+++ b/drivers/media/usb/uvc/uvc_isight.c
@@ -99,9 +99,10 @@ static int isight_decode(struct uvc_video_queue *queue,
struct uvc_buffer *buf,
return 0;
}
-void uvc_video_decode_isight(struct urb *urb, struct uvc_streaming *stream,
+void uvc_video_decode_isight(struct uvc_urb *uu, struct uvc_streaming *stream,
struct uvc_buffer *buf)
{
+ struct urb *urb = uu->urb;
int ret, i;
for (i = 0; i < urb->number_of_packets; ++i) {
diff --git a/drivers/media/usb/uvc/uvc_video.c
b/drivers/media/usb/uvc/uvc_video.c
index f839654..2dfb233 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -379,15 +379,14 @@ static inline void uvc_video_get_ts(struct timespec *ts)
static void
uvc_video_clock_decode(struct uvc_streaming *stream, struct uvc_buffer *buf,
- const __u8 *data, int len)
+ const __u8 *data, int len, u16 host_sof,
+ struct timespec *ts)
{
struct uvc_clock_sample *sample;
unsigned int header_size;
bool has_pts = false;
bool has_scr = false;
unsigned long flags;
- struct timespec ts;
- u16 host_sof;
u16 dev_sof;
switch (data[1] & (UVC_STREAM_PTS | UVC_STREAM_SCR)) {
@@ -435,9 +434,6 @@ uvc_video_clock_decode(struct uvc_streaming *stream, struct
uvc_buffer *buf,
stream->clock.last_sof = dev_sof;
- host_sof = usb_get_current_frame_number(stream->dev->udev);
- uvc_video_get_ts(&ts);
-
/* The UVC specification allows device implementations that can't obtain
* the USB frame number to keep their own frame counters as long as they
* match the size and frequency of the frame number associated with USB
@@ -473,7 +469,7 @@ uvc_video_clock_decode(struct uvc_streaming *stream, struct
uvc_buffer *buf,
sample->dev_stc = get_unaligned_le32(&data[header_size - 6]);
sample->dev_sof = dev_sof;
sample->host_sof = host_sof;
- sample->host_ts = ts;
+ sample->host_ts = *ts;
/* Update the sliding window head and count. */
stream->clock.head = (stream->clock.head + 1) % stream->clock.size;
@@ -964,7 +960,8 @@ static void uvc_video_stats_stop(struct uvc_streaming
*stream)
* uvc_video_decode_end will never be called with a NULL buffer.
*/
static int uvc_video_decode_start(struct uvc_streaming *stream,
- struct uvc_buffer *buf, const __u8 *data, int len)
+ struct uvc_buffer *buf, const __u8 *data, int len,
+ u16 host_sof, struct timespec *ts)
{
__u8 fid;
@@ -989,7 +986,7 @@ static int uvc_video_decode_start(struct uvc_streaming
*stream,
uvc_video_stats_update(stream);
}
- uvc_video_clock_decode(stream, buf, data, len);
+ uvc_video_clock_decode(stream, buf, data, len, host_sof, ts);
uvc_video_stats_decode(stream, data, len);
/* Store the payload FID bit and return immediately when the buffer is
@@ -1016,8 +1013,6 @@ static int uvc_video_decode_start(struct uvc_streaming
*stream,
* when the EOF bit is set to force synchronisation on the next packet.
*/
if (buf->state != UVC_BUF_STATE_ACTIVE) {
- struct timespec ts;
-
if (fid == stream->last_fid) {
uvc_trace(UVC_TRACE_FRAME, "Dropping payload (out of "
"sync).\n");
@@ -1027,13 +1022,11 @@ static int uvc_video_decode_start(struct uvc_streaming
*stream,
return -ENODATA;
}
- uvc_video_get_ts(&ts);
-
buf->buf.v4l2_buf.field = V4L2_FIELD_NONE;
buf->buf.v4l2_buf.sequence = stream->sequence;
- buf->buf.v4l2_buf.timestamp.tv_sec = ts.tv_sec;
+ buf->buf.v4l2_buf.timestamp.tv_sec = ts->tv_sec;
buf->buf.v4l2_buf.timestamp.tv_usec =
- ts.tv_nsec / NSEC_PER_USEC;
+ ts->tv_nsec / NSEC_PER_USEC;
/* TODO: Handle PTS and SCR. */
buf->state = UVC_BUF_STATE_ACTIVE;
@@ -1160,9 +1153,10 @@ static void uvc_video_validate_buffer(const struct
uvc_streaming *stream,
/*
* Completion handler for video URBs.
*/
-static void uvc_video_decode_isoc(struct urb *urb, struct uvc_streaming
*stream,
- struct uvc_buffer *buf)
+static void uvc_video_decode_isoc(struct uvc_urb *uu,
+ struct uvc_streaming *stream, struct uvc_buffer *buf)
{
+ struct urb *urb = uu->urb;
u8 *mem;
int ret, i;
@@ -1180,7 +1174,8 @@ static void uvc_video_decode_isoc(struct urb *urb, struct
uvc_streaming *stream,
mem = urb->transfer_buffer + urb->iso_frame_desc[i].offset;
do {
ret = uvc_video_decode_start(stream, buf, mem,
- urb->iso_frame_desc[i].actual_length);
+ urb->iso_frame_desc[i].actual_length, uu->sof,
+ &uu->ts);
if (ret == -EAGAIN) {
uvc_video_validate_buffer(stream, buf);
buf = uvc_queue_next_buffer(&stream->queue,
@@ -1206,9 +1201,10 @@ static void uvc_video_decode_isoc(struct urb *urb,
struct uvc_streaming *stream,
}
}
-static void uvc_video_decode_bulk(struct urb *urb, struct uvc_streaming
*stream,
- struct uvc_buffer *buf)
+static void uvc_video_decode_bulk(struct uvc_urb *uu,
+ struct uvc_streaming *stream, struct uvc_buffer *buf)
{
+ struct urb *urb = uu->urb;
u8 *mem;
int len, ret;
@@ -1228,7 +1224,8 @@ static void uvc_video_decode_bulk(struct urb *urb, struct
uvc_streaming *stream,
*/
if (stream->bulk.header_size == 0 && !stream->bulk.skip_payload) {
do {
- ret = uvc_video_decode_start(stream, buf, mem, len);
+ ret = uvc_video_decode_start(stream, buf, mem, len,
+ uu->sof, &uu->ts);
if (ret == -EAGAIN)
buf = uvc_queue_next_buffer(&stream->queue,
buf);
@@ -1274,9 +1271,10 @@ static void uvc_video_decode_bulk(struct urb *urb,
struct uvc_streaming *stream,
}
}
-static void uvc_video_encode_bulk(struct urb *urb, struct uvc_streaming
*stream,
- struct uvc_buffer *buf)
+static void uvc_video_encode_bulk(struct uvc_urb *uu,
+ struct uvc_streaming *stream, struct uvc_buffer *buf)
{
+ struct urb *urb = uu->urb;
u8 *mem = urb->transfer_buffer;
int len = stream->urb_size, ret;
@@ -1317,9 +1315,10 @@ static void uvc_video_encode_bulk(struct urb *urb,
struct uvc_streaming *stream,
urb->transfer_buffer_length = stream->urb_size - len;
}
-static void uvc_video_complete(struct urb *urb)
+static void uvc_video_complete(struct uvc_urb *uu)
{
- struct uvc_streaming *stream = urb->context;
+ struct urb *urb = uu->urb;
+ struct uvc_streaming *stream = uu->stream;
struct uvc_video_queue *queue = &stream->queue;
struct uvc_buffer *buf = NULL;
unsigned long flags;
@@ -1349,7 +1348,10 @@ static void uvc_video_complete(struct urb *urb)
queue);
spin_unlock_irqrestore(&queue->irqlock, flags);
- stream->decode(urb, stream, buf);
+ stream->decode(uu, stream, buf);
+
+ if (stream->stop)
+ return;
if ((ret = usb_submit_urb(urb, GFP_ATOMIC)) < 0) {
uvc_printk(KERN_ERR, "Failed to resubmit video URB (%d).\n",
@@ -1357,6 +1359,55 @@ static void uvc_video_complete(struct urb *urb)
}
}
+static void uvc_video_complete_tasklet(unsigned long param)
+{
+ struct uvc_streaming *stream = (struct uvc_streaming *)param;
+ struct urb *urb;
+ unsigned long flags;
+ int i;
+
+ for (i = 0; i < UVC_URBS; i++) {
+ spin_lock_irqsave(&stream->urb_list_lock, flags);
+ if (list_empty(&stream->urb_complete_list)) {
+ spin_unlock_irqrestore(&stream->urb_list_lock, flags);
+ return;
+ }
+ urb = list_first_entry(&stream->urb_complete_list,
+ struct urb, urb_list);
+ list_del(&urb->urb_list);
+ spin_unlock_irqrestore(&stream->urb_list_lock, flags);
+
+ uvc_video_complete(urb->context);
+ }
+}
+
+static void uvc_urb_complete(struct urb *urb)
+{
+ struct uvc_urb *uu = urb->context;
+ struct uvc_streaming *stream = uu->stream;
+ unsigned long flags;
+
+ uu->sof = usb_get_current_frame_number(stream->dev->udev);
+ uvc_video_get_ts(&uu->ts);
+
+ /*
+ * Don't schedule tasklet If hcd is already using tasklet for
+ * completion callback.
+ * Not using !in_interrupt() here as this function can be called
+ * without interrupt context as a result of usb_kill_urb()
+ */
+ if (stream->dev->hcd_uses_bh) {
+ uvc_video_complete(uu);
+ return;
+ }
+
+ spin_lock_irqsave(&stream->urb_list_lock, flags);
+ list_add_tail(&urb->urb_list, &stream->urb_complete_list);
+ spin_unlock_irqrestore(&stream->urb_list_lock, flags);
+
+ tasklet_schedule(&stream->urb_tasklet);
+}
+
/*
* Free transfer buffers.
*/
@@ -1448,14 +1499,29 @@ static void uvc_uninit_video(struct uvc_streaming
*stream, int free_buffers)
uvc_video_stats_stop(stream);
+ /* set stop and make sure no urb is being submitted.*/
+ stream->stop = true;
+ if (!stream->dev->hcd_uses_bh)
+ tasklet_unlock_wait(&stream->urb_tasklet);
+
for (i = 0; i < UVC_URBS; ++i) {
- urb = stream->urb[i];
+ urb = stream->uvc_urb[i].urb;
if (urb == NULL)
continue;
usb_kill_urb(urb);
+ }
+
+ if (!stream->dev->hcd_uses_bh)
+ tasklet_kill(&stream->urb_tasklet);
+
+ for (i = 0; i < UVC_URBS; ++i) {
+ urb = stream->uvc_urb[i].urb;
+ if (urb == NULL)
+ continue;
+
usb_free_urb(urb);
- stream->urb[i] = NULL;
+ stream->uvc_urb[i].urb = NULL;
}
if (free_buffers)
@@ -1514,7 +1580,7 @@ static int uvc_init_video_isoc(struct uvc_streaming
*stream,
}
urb->dev = stream->dev->udev;
- urb->context = stream;
+ urb->context = &stream->uvc_urb[i];
urb->pipe = usb_rcvisocpipe(stream->dev->udev,
ep->desc.bEndpointAddress);
#ifndef CONFIG_DMA_NONCOHERENT
@@ -1525,7 +1591,7 @@ static int uvc_init_video_isoc(struct uvc_streaming
*stream,
#endif
urb->interval = ep->desc.bInterval;
urb->transfer_buffer = stream->urb_buffer[i];
- urb->complete = uvc_video_complete;
+ urb->complete = uvc_urb_complete;
urb->number_of_packets = npackets;
urb->transfer_buffer_length = size;
@@ -1534,7 +1600,8 @@ static int uvc_init_video_isoc(struct uvc_streaming
*stream,
urb->iso_frame_desc[j].length = psize;
}
- stream->urb[i] = urb;
+ stream->uvc_urb[i].urb = urb;
+ stream->uvc_urb[i].stream = stream;
}
return 0;
@@ -1580,14 +1647,15 @@ static int uvc_init_video_bulk(struct uvc_streaming
*stream,
}
usb_fill_bulk_urb(urb, stream->dev->udev, pipe,
- stream->urb_buffer[i], size, uvc_video_complete,
- stream);
+ stream->urb_buffer[i], size, uvc_urb_complete,
+ &stream->uvc_urb[i]);
#ifndef CONFIG_DMA_NONCOHERENT
urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
urb->transfer_dma = stream->urb_dma[i];
#endif
- stream->urb[i] = urb;
+ stream->uvc_urb[i].urb = urb;
+ stream->uvc_urb[i].stream = stream;
}
return 0;
@@ -1611,6 +1679,12 @@ static int uvc_init_video(struct uvc_streaming *stream,
gfp_t gfp_flags)
uvc_video_stats_start(stream);
+ tasklet_init(&stream->urb_tasklet, uvc_video_complete_tasklet,
+ (unsigned long)stream);
+ INIT_LIST_HEAD(&stream->urb_complete_list);
+ spin_lock_init(&stream->urb_list_lock);
+ stream->stop = false;
+
if (intf->num_altsetting > 1) {
struct usb_host_endpoint *best_ep = NULL;
unsigned int best_psize = UINT_MAX;
@@ -1678,7 +1752,7 @@ static int uvc_init_video(struct uvc_streaming *stream,
gfp_t gfp_flags)
/* Submit the URBs. */
for (i = 0; i < UVC_URBS; ++i) {
- ret = usb_submit_urb(stream->urb[i], gfp_flags);
+ ret = usb_submit_urb(stream->uvc_urb[i].urb, gfp_flags);
if (ret < 0) {
uvc_printk(KERN_ERR, "Failed to submit URB %u "
"(%d).\n", i, ret);
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index 816dd1a..0633d8a 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -440,6 +440,13 @@ struct uvc_stats_stream {
unsigned int max_sof; /* Maximum STC.SOF value */
};
+struct uvc_urb {
+ struct urb *urb;
+ struct uvc_streaming *stream;
+ struct timespec ts;
+ u16 sof;
+};
+
struct uvc_streaming {
struct list_head list;
struct uvc_device *dev;
@@ -470,7 +477,7 @@ struct uvc_streaming {
/* Buffers queue. */
unsigned int frozen : 1;
struct uvc_video_queue queue;
- void (*decode) (struct urb *urb, struct uvc_streaming *video,
+ void (*decode)(struct uvc_urb *uu, struct uvc_streaming *video,
struct uvc_buffer *buf);
/* Context data used by the bulk completion handler. */
@@ -482,7 +489,11 @@ struct uvc_streaming {
__u32 max_payload_size;
} bulk;
- struct urb *urb[UVC_URBS];
+ bool stop;
+ spinlock_t urb_list_lock;
+ struct list_head urb_complete_list;
+ struct tasklet_struct urb_tasklet;
+ struct uvc_urb uvc_urb[UVC_URBS];
char *urb_buffer[UVC_URBS];
dma_addr_t urb_dma[UVC_URBS];
unsigned int urb_size;
@@ -550,6 +561,7 @@ struct uvc_device {
__u8 *status;
struct input_dev *input;
char input_phys[64];
+ bool hcd_uses_bh;
};
enum uvc_handle_state {
@@ -728,7 +740,7 @@ extern struct usb_host_endpoint *uvc_find_endpoint(
struct usb_host_interface *alts, __u8 epaddr);
/* Quirks support */
-void uvc_video_decode_isight(struct urb *urb, struct uvc_streaming *stream,
+void uvc_video_decode_isight(struct uvc_urb *uu, struct uvc_streaming *stream,
struct uvc_buffer *buf);
/* debugfs and statistics */
--
2.3.3
--
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