Date: Fri, 28 Oct 2005 15:57:15 -0700 From: Bharma Ji <bharmaji@gmail.com> To: freebsd-drivers@freebsd.org Subject: Re: Recommended ways to log driver operations Message-ID: <67beabb0510281557k5d237a0br9b586bdde35c6971@mail.gmail.com> In-Reply-To: <20051017.210955.104032631.imp@bsdimp.com> References: <67beabb0510171825q1e124bf6v2adbe0c9f235a6ae@mail.gmail.com> <20051017.210955.104032631.imp@bsdimp.com>
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Resurrecting a recent thread... Thanks for your resposne. ktr and alq are unfortunately not availabe on the freebsd version that I am using. I have reduced my requirements for the logging facility. Now all I require is that the log be persistent. The problem that I face is that in the event of a kernel panic - the driver messages are all lost.Is there a way to writ= e the messages to the disk while the driver is executing.(seems to much to as= k probably - but someone somewhere would have thought of a way around it) On 10/17/05, M. Warner Losh <imp@bsdimp.com> wrote: > > In message: <67beabb0510171825q1e124bf6v2adbe0c9f235a6ae@mail.gmail.com> > Bharma Ji <bharmaji@gmail.com> writes: > : I recently wrote a driver for a chip. I am wondering if there are any > : standard recommended ways of logging the driver operations. I have used > : printf in the driver and I look at it using dmesg so far. Am wondering > if it > : is possible to create a driver specific log file so that it is easy to > : debug. Also, if the driver emits copious output then the log buffer wil= l > : overflow and some messages may be truncated. Writing to a specific log > file > : may help in that case. However, I have no idea if this is worth > : investigating. Any suggestions appreciated > > printf(9) doesn't give you much of a chance to segregate the logs. You > can also use log(9), but that just adds the ability to give a priority > to the log message, which can help. > > If you want to debug the driver to find out what's going on at a high > rate, you might want to look at ktr(9) and alq(9). These facilities > are more for debugging and performance tuning, rather than day to day > operations. In general, FreeBSD drivers follow the unix tradition of > only complaining when there are problems. > > Warner >
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