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Revert 7e92b4fc345f5b6f57585fbe5ffdb0f24d7c9b26. It broke Sébastien Dugué's
machine and Jeff said (persuasively)
This seems like it will break decades-long-working stuff, in favor of
breaking new ground in our favorite area, "trusting the BIOS."
It's just not worth it for serial ports, IMO. Serial ports are something
that just shouldn't break at this late stage in the game. My new Intel
platform boxes don't even have serial ports, so I question the value of
messing with serial port probing even more... because... just wait a year,
and your box won't have a serial port either! :)
I certainly don't object to the use of platform devices (or isa_driver),
but the probe change seems questionable. That's sorta analagous to
rewriting the floppy driver probe routine. Sure you could do it... but why
risk all that damage and go through debugging all over again?
It seems clear from this report that we cannot, should not, trust BIOS for
something (a) so simple and (b) that has been working for over a decade.
Much discussion ensued and we've decided to have another go at all of this.
Cc: Sébastien Dugué <sebastien.dugue@bull.net>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Adam Belay <ambx1@neo.rr.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Jeff Garzik <jeff@garzik.org>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Michal Piotrowski <michal.k.k.piotrowski@gmail.com>
Cc: Sascha Sommer <saschasommer@freenet.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Make x86 COM ports into platform devices and don't probe for them
if we have PNP.
This prevents double discovery, where a device was found both by
the legacy probe and by 8250_pnp, e.g.,
serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
00:02: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
This also means IRDA devices without a UART PNP ID will no longer be
claimed by the serial driver, which might require changes in IRDA
drivers and administration.
In addition to this patch, you may need to configure a setserial init
script, e.g., /etc/init.d/setserial, so it doesn't poke legacy UART
stuff back in. On Debian, "dpkg-reconfigure setserial" with the "kernel"
option does this.
To force the old legacy probe behavior even when we have PNPBIOS or
ACPI, load the new legacy_serial module (or build 8250 static) with
the "legacy_serial.force" option.
[akpm@linux-foundation.org: fix makefiles]
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Keith Owens <kaos@ocs.com.au>
Cc: Len Brown <lenb@kernel.org>
Cc: Adam Belay <ambx1@neo.rr.com>
Cc: Matthieu CASTET <castet.matthieu@free.fr>
Cc: Jean Tourrilhes <jt@hpl.hp.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Ville Syrjala <syrjala@sci.fi>
Cc: Russell King <rmk+serial@arm.linux.org.uk>
Cc: Samuel Ortiz <samuel@sortiz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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