tree d9502baa72354fa85ff8aae9cdd4062d16147b71 parent f2ecc3d0787e05d9145722feed01d4a11ab6bec1 author Sean Young 1510175985 -0500 committer Mauro Carvalho Chehab 1510754254 -0500 media: rc: sir_ir: detect presence of port Without this test, sir_ir clumsy claims resources for a device which does not exist. The 0-day kernel test robot reports the following errors (in a loop): sir_ir sir_ir.0: Trapped in interrupt genirq: Flags mismatch irq 4. 00000000 (ttyS0) vs. 00000000 (sir_ir) When sir_ir is loaded with the default io and irq, the following happens: - sir_ir claims irq 4 - user space opens /dev/ttyS0 - in serial8250_do_startup(), some setup is done for ttyS0, which causes irq 4 to fire (in THRE test) - sir_ir does not realise it was not for it, and spins until the "trapped in interrupt" - now serial driver calls setup_irq() and fails and we get the "Flags mismatch" error. There is no port present at 0x3e8 so simply check for the presence of a port, as suggested by Linus. Reported-by: kbuild test robot Tested-by: Fengguang Wu Signed-off-by: Sean Young Cc: # 4.12+ Signed-off-by: Mauro Carvalho Chehab