Hello Tejun, On Tue, Nov 29, 2016 at 2:41 PM, Tejun Heo <tj@xxxxxxxxxx> wrote: > Hello, Matthew. > > (cc'ing Bartlomiej) > > On Tue, Nov 29, 2016 at 12:53:02PM -0500, Matthew Whitehead wrote: >> If there is no PCI bus detected in drivers/ata/pata_legacy.c, it registers all the >> common legacy PATA devices. This includes I/O ports (0x1f0, 0x170, 0x1e8, 0x168, 0x1e0, 0x160) >> and also their associated interrupts (14,15,11,10,8,12). >> >> Unfortunately, on such systems those interrupt lines are at a premium because there is no >> PCI alternative. This patch allows you to disable individual port/interrupt pairs by providing >> a list of ports to skip allocating. >> >> modprobe pata_legacy ignore_ports=0x1e8,0x168,0x1e0,0x160 > > Can you please give a concrete example of a machine and situation > where this would be useful? > Sure, my regression testing i486 system has this problem. It only has an EISA bus, no PCI. I had to apply the patch to be able to put even 2-3 cards in it. It had run out of IRQs. This testing helped uncover a long time kernel bug that now has a patch. http://git.kernel.org/cgit/linux/kernel/git/tip/tip.git/commit/?id=fc0e81b2bea0ebceb71889b61d2240856141c9ee Please check the linux-kernel mailing list thread "What exactly do 32-bit x86 exceptions push on the stack in the CS slot?" for more details. https://lkml.org/lkml/2016/11/19/308 - Matthew -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
