Messages in this thread | | | Date | Sun, 8 Sep 1996 18:59:53 -0700 | From | "Leonard N. Zubkoff" <> | Subject | Re: writing to POST leds? |
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Date: Sun, 8 Sep 1996 17:53:25 -0500 (CDT) From: Edward Welbon <welbon@bga.com>
I have a POST (Power On Self Test) display card that registers and displays the POST values on LEDs. I have removed the useless clock speed LEDs with POST codes instead since in addition to the BIOS, the kernel etc. writes to them. The address is IO port 80. Here is the dumb question, since I doubt that the meanings of the values are documented anywhere, how might I find places where the code references them. As you might guess, I am not entirely clear on how to write to the LEDs. Is there any standard way?
I have one of these also. It's useful for debugging device drivers when printk's perturb the environment enough to make a bug disappear. All you need to do is output a value to port 0x80. However, the SLOW_DOWN_IO code in asm/io.h writes random values to port 0x80, which tends to obscure the values written by users.
Leonard
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