Re: [PATCH 5/5] firewire: ohci: add tracepoints event for data of Self-ID DMA
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From: Takashi S. <o-t...@sa...> - 2024-07-04 00:07:17
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Hi, On Wed, Jul 03, 2024 at 07:20:34AM +0900, Takashi Sakamoto wrote: > In 1394 OHCI, the SelfIDComplete event occurs when the hardware has > finished transmitting all of the self ID packets received during the bus > initialization process to the host memory by DMA. > > This commit adds a tracepoints event for this event to trace the timing > and packet data of Self-ID DMA. It is the part of following tracepoints > events helpful to debug some events at bus reset; e.g. the issue addressed > at a commit d0b06dc48fb1 ("firewire: core: use long bus reset on gap count > error")[1]: > > * firewire_ohci:irqs > * firewire_ohci:self_id_complete > * firewire:bus_reset_handle > * firewire:self_id_sequence > > They would be also helpful in the problem about invocation timing of > hardIRQ/softIRQ contexts. We can often see this kind of problem with -rt > kernel[2]. Oops, I misunderstood. The handling of Self-ID DMA buffer is in hardIRQ and process (workqueue) contexts, thus the above issue is not the invocation timing of hardIRQ/softIRQ contexts. Let me correct it at the applied commit comment. > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d0b06dc48fb1 > [2] https://lore.kernel.org/linux-rt-users/YAwPoaUZ1gTD5y+k@hmbx/ > > Signed-off-by: Takashi Sakamoto <o-t...@sa...> > --- > drivers/firewire/ohci.c | 11 +++++- > include/trace/events/firewire_ohci.h | 54 ++++++++++++++++++++++++++++ > 2 files changed, 64 insertions(+), 1 deletion(-) Regards Takashi Sakamoto |