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 <mat...@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
