From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20060202 Fedora/1.0.7-1.2.fc4 Firefox/1.0.7 Description of problem: /var/log/messages of 2.6.15 boot: kernel: Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing enabled kernel: serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A kernel: serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A kernel: 00:09: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A kernel: 00:0a: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A kernel: ACPI: PCI Interrupt Link [LNKC] enabled at IRQ 11 kernel: PCI: setting IRQ 11 as level-triggered kernel: ACPI: PCI Interrupt 0000:02:0e.0[A] -> Link [LNKC] -> GSI 11 (level, low) -> IRQ 11 kernel: 0000:02:0e.0: ttyS2 at I/O 0xa800 (irq = 11) is a 16550A kernel: 0000:02:0e.0: ttyS3 at I/O 0xa400 (irq = 11) is a 16550A Older 2.6.14 kernels: kernel: Serial: 8250/16550 driver $Revision: 1.90 $ 32 ports, IRQ sharing enabled kernel: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A kernel: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A kernel: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A kernel: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A kernel: ACPI: PCI Interrupt Link [LNKC] enabled at IRQ 11 kernel: PCI: setting IRQ 11 as level-triggered kernel: ACPI: PCI Interrupt 0000:02:0e.0[A] -> Link [LNKC] -> GSI 11 (level, low) -> IRQ 11 kernel: ttyS4 at I/O 0xa800 (irq = 11) is a 16550A kernel: ttyS5 at I/O 0xa400 (irq = 11) is a 16550A kernel: ACPI: PCI Interrupt 0000:02:0e.1[A] -> Link [LNKC] -> GSI 11 (level, low) -> IRQ 11 kernel: ttyS6 at I/O 0xa000 (irq = 11) is a 16550A kernel: ttyS7 at I/O 0x9800 (irq = 11) is a 16550A Version-Release number of selected component (if applicable): kernel-2.6.15-1.1830_FC4 How reproducible: Always Steps to Reproduce: 1. Boot-up 2. 3. Actual Results: 2 out of my 6 serial ports were not found. 2 ports had their port numbers changed when comparing to previous kernels. Expected Results: Same as with 2.6.14 and before. Additional info: lspci -v (2.6.14): 02:0e.0 Serial controller: Lava Computer mfg Inc Quattro-PCI A (prog-if 02 [16550]) Flags: slow devsel, IRQ 11 I/O ports at a800 [size=8] I/O ports at a400 [size=8] 02:0e.1 Serial controller: Lava Computer mfg Inc Quattro-PCI B (prog-if 02 [16550]) Flags: slow devsel, IRQ 11 I/O ports at a000 [size=8] I/O ports at 9800 [size=8]
The log above were missing two important lines: kernel: ACPI: PCI Interrupt 0000:02:0e.1[A] -> Link [LNKC] -> GSI 11 (level, low) -> IRQ 11 kernel: Couldn't register serial port 0000:02:0e.1: -28
Same behaviour observed with a clone 8-port PCI serial card on x86. /var/log/messages of 2.6.14-1.1656_FC4 kernel: Serial: 8250/16550 driver $Revision: 1.90 $ 32 ports, IRQ sharing enabled kernel: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A (motherboard COMA) kernel: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A (motherboard COMB) kernel: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A kernel: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A kernel: ACPI: PCI Interrupt Link [LNKB] enabled at IRQ 10 kernel: PCI: setting IRQ 10 as level-triggered kernel: ACPI: PCI Interrupt 0000:02:05.0[A] -> Link [LNKB] -> GSI 10 (level, low) -> IRQ 10 kernel: ttyS4 at I/O 0xb400 (irq = 10) is a 16550A (PCI card port 1) kernel: ttyS5 at I/O 0xb000 (irq = 10) is a 16550A (PCI card port 2) kernel: ttyS6 at I/O 0xac00 (irq = 10) is a 16550A (PCI card port 3) kernel: ttyS7 at I/O 0xa800 (irq = 10) is a 16550A (PCI card port 4) kernel: ttyS8 at I/O 0xa400 (irq = 10) is a 16550A (PCI card port 5) kernel: ttyS9 at I/O 0xa408 (irq = 10) is a 16550A (PCI card port 6) kernel: ttyS10 at I/O 0xa410 (irq = 10) is a 16550A (PCI card port 7) kernel: ttyS11 at I/O 0xa418 (irq = 10) is a 16550A (PCI card port 8) /var/log/messages of 2.6.15-1.1831_FC4 kernel: Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing enabled kernel: serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A kernel: serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A kernel: 00:09: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A kernel: 00:0a: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A kernel: ACPI: PCI Interrupt Link [LNKB] enabled at IRQ 10 kernel: PCI: setting IRQ 10 as level-triggered kernel: ACPI: PCI Interrupt 0000:02:05.0[A] -> Link [LNKB] -> GSI 10 (level, low) -> IRQ 10 kernel: 0000:02:05.0: ttyS2 at I/O 0xb400 (irq = 10) is a 16550A kernel: 0000:02:05.0: ttyS3 at I/O 0xb000 (irq = 10) is a 16550A kernel: Couldn't register serial port 0000:02:05.0: -28 With 2.6.15, /dev/ttyS0-3 are created (standard x86 hardware only has COMA & COMB) ; no sign of higher 8 ports. Older kernels are AOK. $ lspci -v <snip> 02:05.0 Serial controller: AFAVLAB Technology Inc: Unknown device 2180 (prog-if 02 [16550]) Subsystem: AFAVLAB Technology Inc: Unknown device 2180 Flags: medium devsel, IRQ 10 I/O ports at b400 [size=8] I/O ports at b000 [size=8] I/O ports at ac00 [size=8] I/O ports at a800 [size=8] I/O ports at a400 [size=32] Capabilities: [a0] Power Management version 1 <snip> Looks like an upstream kernel bug as 2.6.15-1.1830 notes shows activity in the serial code. Googling shows a similar bug report in debbugs.org .
boot with the parameter 8250.nr_uarts=6 (or however many you have).
Tested OK. Note: number of ports is (4 legacy ports COM1-4) + (number of extras) I've got a PCI 8 port board, so used 12. Boot and use built-in editor to add the parameter to the end of the kernel line. Edited /boot/grub.conf to add 8250.nr_uarts=12: title Fedora Core (2.6.15-1.1831_FC4) root (hd0,0) kernel /vmlinuz-2.6.15-1.1831_FC4 ro root=/dev/VolGroup00/LogVol00 rhgb quiet 8250.nr_uarts=12 initrd /initrd-2.6.15-1.1831_FC4.img Ports show up as /dev/ttyS4-11. Thanks!