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Subject[PATCH v6 1/2] media: usb: pwc: Introduce TRACE_EVENTs for pwc_isoc_handler()
Date
There were reports that PWC-based webcams don't work at some
embedded ARM platforms. [1] Isochronous transfer handler seems to
work too long leading to the issues in MUSB USB host subsystem.
Also note, that urb->giveback() handlers are still called with
disabled interrupts. In order to be able to measure performance of
PWC driver, traces are introduced in URB handler section.

[1] https://www.spinics.net/lists/linux-usb/msg165735.html

Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
---
drivers/media/usb/pwc/pwc-if.c | 7 +++++
include/trace/events/pwc.h | 65 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 72 insertions(+)
create mode 100644 include/trace/events/pwc.h

diff --git a/drivers/media/usb/pwc/pwc-if.c b/drivers/media/usb/pwc/pwc-if.c
index 72704f4d5330..53c111bd5a22 100644
--- a/drivers/media/usb/pwc/pwc-if.c
+++ b/drivers/media/usb/pwc/pwc-if.c
@@ -76,6 +76,9 @@
#include "pwc-dec23.h"
#include "pwc-dec1.h"

+#define CREATE_TRACE_POINTS
+#include <trace/events/pwc.h>
+
/* Function prototypes and driver templates */

/* hotplug device table support */
@@ -260,6 +263,8 @@ static void pwc_isoc_handler(struct urb *urb)
int i, fst, flen;
unsigned char *iso_buf = NULL;

+ trace_pwc_handler_enter(urb, pdev);
+
if (urb->status == -ENOENT || urb->status == -ECONNRESET ||
urb->status == -ESHUTDOWN) {
PWC_DEBUG_OPEN("URB (%p) unlinked %ssynchronously.\n",
@@ -348,6 +353,8 @@ static void pwc_isoc_handler(struct urb *urb)
}

handler_end:
+ trace_pwc_handler_exit(urb, pdev);
+
i = usb_submit_urb(urb, GFP_ATOMIC);
if (i != 0)
PWC_ERROR("Error (%d) re-submitting urb in pwc_isoc_handler.\n", i);
diff --git a/include/trace/events/pwc.h b/include/trace/events/pwc.h
new file mode 100644
index 000000000000..a2da764a3b41
--- /dev/null
+++ b/include/trace/events/pwc.h
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#if !defined(_TRACE_PWC_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_PWC_H
+
+#include <linux/usb.h>
+#include <linux/tracepoint.h>
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM pwc
+
+TRACE_EVENT(pwc_handler_enter,
+ TP_PROTO(struct urb *urb, struct pwc_device *pdev),
+ TP_ARGS(urb, pdev),
+ TP_STRUCT__entry(
+ __field(struct urb*, urb)
+ __field(struct pwc_frame_buf*, fbuf)
+ __field(int, urb__status)
+ __field(u32, urb__actual_length)
+ __field(int, fbuf__filled)
+ __string(name, pdev->v4l2_dev.name)
+ ),
+ TP_fast_assign(
+ __entry->urb = urb;
+ __entry->fbuf = pdev->fill_buf;
+ __entry->urb__status = urb->status;
+ __entry->urb__actual_length = urb->actual_length;
+ __entry->fbuf__filled = (pdev->fill_buf
+ ? pdev->fill_buf->filled : 0);
+ __assign_str(name, pdev->v4l2_dev.name);
+ ),
+ TP_printk("dev=%s (fbuf=%p filled=%d) urb=%p (status=%d actual_length=%u)",
+ __get_str(name),
+ __entry->fbuf,
+ __entry->fbuf__filled,
+ __entry->urb,
+ __entry->urb__status,
+ __entry->urb__actual_length)
+);
+
+TRACE_EVENT(pwc_handler_exit,
+ TP_PROTO(struct urb *urb, struct pwc_device *pdev),
+ TP_ARGS(urb, pdev),
+ TP_STRUCT__entry(
+ __field(struct urb*, urb)
+ __field(struct pwc_frame_buf*, fbuf)
+ __field(int, fbuf__filled)
+ __string(name, pdev->v4l2_dev.name)
+ ),
+ TP_fast_assign(
+ __entry->urb = urb;
+ __entry->fbuf = pdev->fill_buf;
+ __entry->fbuf__filled = pdev->fill_buf->filled;
+ __assign_str(name, pdev->v4l2_dev.name);
+ ),
+ TP_printk(" dev=%s (fbuf=%p filled=%d) urb=%p",
+ __get_str(name),
+ __entry->fbuf,
+ __entry->fbuf__filled,
+ __entry->urb)
+);
+
+#endif /* _TRACE_PWC_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
--
2.16.4
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