Messages in this thread | | | Date | Wed, 14 Jan 2004 14:32:01 -0800 | From | George Anzinger <> | Subject | Re: [discuss] Re: kgdb for x86_64 2.6 kernels |
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Amit S. Kale wrote: > On Wednesday 14 Jan 2004 2:56 am, George Anzinger wrote: > >>Amit S. Kale wrote: >> >>>8250.patch changes generic 8250/16550 driver behavior only in following >>>ways 1. It adds a function serial8250_release_irq to release those serial >>>ports which share an irq with kgdb irq. >>>2. There are checks so that a serial port that uses an irq used by an >>>initialized kgdb can't be initialized or started. >>> >>>File kgdb_8250.c is independent of 8250.c kgdb_8250.c depends on >>>KGDB_8250 and 8250.c depends on SERIAL_8250 which can be independently >>>configured. kgdb_8250.c can be compiled even if 8250.c is not included. >>>kgdb_8250.c does only the _minimum_ set of initializations required by >>>hardware. >> >>Ok. >> >> >>>Serial interface should be configurable independent of kgdb and may not >>>be configured if ethernet interface is configured. Serial interface is >>>far simpler hence superior for debugging purposes. If it's available, >>>using ethernet interface is out of question. Ethernet interface can be >>>used when serial hardware isn't present or is being used for some other >>>purposes. >> >>I rather think that the serial inteface should be the fall back unless the >>user has told us at configure time that it is not available. I am not >>prepared to make a statment that it is better than eth. The eth intface >>should be much faster, but it has its fingers into a large part of the >>kernel that MAY be the subject of the current session. Thus, I think that >>eth may be better, IF one is clearly not involved in debugging those areas >>of the kernel. (Which, by the way, we need to enumerate at some point.) > > > Ethernet interface spans a large part of the kernel, so is going to be limited > in near future. When it becomes as minimal as the serial interface, both may > be given equal priority. > > At 115kbps, serial interface is usable even when doing a thread list of 200 > threads.
Only 200? :)
Yes, I agree, but the thing I see about the eth interface is that it allows much more remote debugging, like accrost the country, and it is every so much easier to set up. I don't know about you, but my experience with rs232, which after all, can only be wired one of two ways, it that the probability of getting it wrong is about 90%.
-g -- George Anzinger george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml
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