From: "Wangnan (F)" <wangnan0@huawei.com>
To: <mathieu.poirier@linaro.org>,
xiakaixu 00238161 <xiakaixu@huawei.com>, <suzuki.poulose@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>
Subject: coresight: Problem caused by resetting enable_sink
Date: Mon, 26 Dec 2016 17:17:08 +0800 [thread overview]
Message-ID: <6598d4c2-bbfb-1792-d216-a15ab0e841e0@huawei.com> (raw)
Hi Mathieu,
I meet problems caused by your commit d52c9750f150 ('coresight:
reset "enable_sink" flag when need be'). Not only the one I
posted in the previous patch.
My use case is a simple 'perf record -e cs_etm// ls'. It works
properly before this commit, and failed when allocating aux buffer
after your commit. I can't fully understand your code, but the
problem I meet seems caused by inappropriately reseting sink.
My device is connected like this (use two etfs):
Core0--+
Core1--+-- funnel0 --> etf0
Core2--|
Core3--+
Core0--+
Core1--+-- funnel1 --> etf1
Core2--|
Core3--+
Before running perf, two etfs are activated using sysfs
enable_sink interface.
During etm_setup_aux, coresight_get_enabled_sink() finds
etf0 for core0, and automatically deactivates it.
For core1, coresight_get_enabled_sink() returns etf1.
However, etf1 is not on the link of core1, so following
coresight_build_path() fails.
I guess your commit is based on the assumption that all
sinks are in the patch for each cores. Like this:
Core0--+
Core1--+-- funnel0 --> etf0 ++
Core2--| | +--- etr
Core3--+ | |
+ replicator +
Core0--+ | |
Core1--+-- funnel1 --> etf1 ++ +--- etb
Core2--|
Core3--+
But it is not true, at least for some hisilicon board.
I have to revert your patch to make CoreSight on my board
work. Please reconsider this patch, or please give some
suggestion if you think I misunderstood your patch.
Thank you.
next reply other threads:[~2016-12-26 9:27 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-26 9:17 Wangnan (F) [this message]
2017-01-03 18:34 ` coresight: Problem caused by resetting enable_sink Mathieu Poirier
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=6598d4c2-bbfb-1792-d216-a15ab0e841e0@huawei.com \
--to=wangnan0@huawei.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mathieu.poirier@linaro.org \
--cc=suzuki.poulose@arm.com \
--cc=xiakaixu@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).