From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Date: Tue, 15 Jul 2003 13:11:25 +0000 Subject: Serial port numbering still broken in 2.5.75 Message-Id: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org This is with 2.5.75: Serial: 8250/16550 driver $Revision: 1.90 $ IRQ sharing enabled ttyS0 at MMIO 0xf0200019000 (irq = 54) is a 16550A PCI: Found IRQ 54 for device 0002:00:00.0 ttyS14 at MMIO 0xf0200018000 (irq = 54) is a 16550A PCI: Found IRQ 54 for device 0002:00:00.1 ttyS15 at MMIO 0xf0200019010 (irq = 54) is a 16550A ttyS1 at MMIO 0xf0200019038 (irq = 54) is a 16550A PCI: Found IRQ 92 for device 0003:00:00.0 ttyS2 at MMIO 0xf0300018000 (irq = 92) is a 16550A PCI: Found IRQ 92 for device 0003:00:00.1 ttyS3 at MMIO 0xf0300019000 (irq = 92) is a 16550A ttyS4 at MMIO 0xf0300019010 (irq = 92) is a 16550A ttyS5 at MMIO 0xf0300019038 (irq = 92) is a 16550A Non-legacy serial ports are numbered 0, 14, 15, 1, 2, 3, 4, 5. This is because of this part of uart_find_match_or_unused() in drivers/serial/core.c: /* * We didn't find a matching entry, so look for the first * free entry. We look for one which hasn't been previously * used (indicated by zero iobase). */ for (i = 0; i < drv->nr; i++) if (drv->state[i].port->type = PORT_UNKNOWN && drv->state[i].port->iobase = 0 && drv->state[i].count = 0) return &drv->state[i]; If you look in include/asm-ia64/serial.h, you'll see ttyS14 and ttyS15 marked as `spare', and these are the ones found by uart_find_match_or_unused() first [the first port gets to be ttyS0 because of how 8250_hcdp works]. I think this loop needs to be deleted from uart_find_match_or_unused() so we don't attempt to use 14/15 first. Alternatively, we could just fill in some random iobases in include/asm-ia64/serial.h so this loop always fails on ia64. But I've seen people complaining about their modem getting ttyS14 on i386 too, so I really think this needs to get fixed for everyone. -- "It's not Hollywood. War is real, war is primarily not about defeat or victory, it is about death. I've seen thousands and thousands of dead bodies. Do you think I want to have an academic debate on this subject?" -- Robert Fisk