Messages in this thread | | | Date | Wed, 13 Aug 2003 19:34:18 +0100 | From | Russell King <> | Subject | Re: Bogus serial port ttyS02 |
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On Wed, Aug 13, 2003 at 05:40:23PM +0200, Geert Uytterhoeven wrote: > Linux always finds 3 serial ports instead of 2: > > | ttyS00 at 0x03f8 (irq = 4) is a 16550A > | ttyS01 at 0x02f8 (irq = 3) is a 16550A > | ttyS02 at 0x03e8 (irq = 4) is a 16450 > > The last one is bogus.
Do you know that it absolutely does not exist? Can it exist on any PPC box? If the answer to both those questions is no, I suggest you don't probe for it in the first place.
You could enable DEBUG_AUTOCONF in 8250.c in 2.6.0-test3 and give further probing information. 8)
Looking at PPC's pc_serial.h, it seems that you've told it to probe there using ASYNC_BOOT_AUTOCONF | ASYNC_SKIP_TEST | ASYNC_AUTO_IRQ.
ASYNC_SKIP_TEST means that we use a reduced test to probe for a port - we just check that we can read back a value written to 0x3e9. If this suceeds, we decide that there is a port present, and go on to try and derive its type.
If you want to enable the more rigorous tests, remove ASYNC_SKIP_TEST from the port flags. This will make us check that the device behaves like a UART before deciding that it is one.
-- Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux http://www.arm.linux.org.uk/personal/aboutme.html
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