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From: Johannes Stezenbach <js@sig21.net>
To: Jason Baron <jbaron@redhat.com>
Cc: linux-kernel@vger.kernel.org,
	Alan Stern <stern@rowland.harvard.edu>,
	linux-usb@vger.kernel.org
Subject: ehci dynamic debug problem
Date: Fri, 13 Apr 2012 10:56:07 +0200	[thread overview]
Message-ID: <20120413085607.GA18024@sig21.net> (raw)

Hi,

I have a quirky device and enabled dynamic debug to
see the ehci driver debug messages to help me diagnose
the problem.  I see stuff like this:

[1790542.363321] ehci_hub_control:940: ehci_hcd 0000:00:1a.0: \xffffffd8\xffffff94\xffffff94\xffffffa8\xffffff81\xffffffff\xffffffff\xffffffff\xffffffff}[<\xffffff81\xffffffff\xffffffff\xffffffff\xffffffff\x01
[1790542.363470] ehci_hub_control:940: ehci_hcd 0000:00:1a.0: \xffffffd8\xffffff94\xffffff94\xffffffa8\xffffff81\xffffffff\xffffffff\xffffffff\xffffffff}[<\xffffff81\xffffffff\xffffffff\xffffffff\xffffffff\x01

The problem is in ehci-dbg.c:

#define dbg_port(ehci, label, port, status) { \
	char _buf [80]; \
	dbg_port_buf (_buf, sizeof _buf, label, port, status); \
	ehci_dbg (ehci, "%s\n", _buf); \
}

dbg_port_buf() is a no op when DEBUG is not defined, thus
the ehci_dbg() prints uninitialized memory.


Does dynamic debug offer an "is the message two lines below enabled" test?
Simply changing the "#ifdef DEBUG" for dbg_port_buf()
to "#if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)"
is probably not acceptable due to the overhead of dbg_port_buf()?


Thanks,
Johannes

             reply	other threads:[~2012-04-13  8:56 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-13  8:56 Johannes Stezenbach [this message]
2012-04-13 14:35 ` ehci dynamic debug problem Alan Stern
2012-04-13 14:57   ` Johannes Stezenbach
2012-04-13 15:19     ` Alan Stern
2012-04-13 17:41       ` Johannes Stezenbach
2012-04-13 18:13         ` Alan Stern
2012-04-13 19:03           ` Johannes Stezenbach
2012-04-13 19:40             ` Alan Stern
2012-04-16 15:11             ` Alan Stern
2012-04-16 15:54             ` Jason Baron
2012-04-16 16:41               ` Johannes Stezenbach
2012-04-16 17:15                 ` Jason Baron
2012-04-16 19:07                   ` Johannes Stezenbach

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