On Feb 17, 2019, Aaro Koskinen <aaro.koski...@iki.fi> wrote: > I tested few older kernels, and it seems that the spurious IRQ issue has > been always there after switching to libata (commit 7ff7a5b1bfff). It has > been unnoticed as the 100000 irq limit wasn't reached during boot.
I see, thanks. That would probably make it hard to bisect indeed. >> The kernel still disables irq14 early on, and then runs slow. > This hack works only for CONFIG_PATA_CS5536. You are probably using PATA_AMD. That's a reasonable guess, but I don't think so. I do have PATA_AMD enabled as a module indeed, but it's not even loaded, much as I can tell, whereas PATA_CS5536 is built into the kernel image, and dmesg says: [ 4.460000] scsi host0: pata_cs5536 [ 4.464000] scsi host1: pata_cs5536 [ 4.464000] ata1: PATA max UDMA/100 cmd 0x1f0 ctl 0x3f6 bmdma 0x4c60 irq 14 [ 4.464000] ata2: DUMMY [ 4.464000] pcnet32: [...] [ 4.644000] random: [...] [ 5.908000] irq 14: nobody cared (try booting with the "irqpoll" option) Just to be sure, I added some printks to cs5536_noop_freeze, and here's what I got in dmesg instead: [ 4.452000] pata_cs5536: freeze: checking status... [ 4.452000] pata_cs5536: freeze: checked, clearing... [ 4.452000] pata_cs5536: freeze: cleared [ 4.460000] scsi host0: pata_cs5536 [ 4.464000] scsi host1: pata_cs5536 [ 4.464000] ata1: PATA max UDMA/100 cmd 0x1f0 ctl 0x3f6 bmdma 0x4c60 irq 14 [ 4.464000] ata2: DUMMY [ 4.464000] pcnet32: [...] [ 4.468000] pata_cs5536: freeze: checking status... [ 4.468000] pata_cs5536: freeze: checked, clearing... [ 4.468000] pata_cs5536: freeze: cleared [ 4.652000] random: [...] [ 5.920000] irq 14: nobody cared (try booting with the "irqpoll" option) now, maybe I just don't understand what effects the patch was supposed to have. The system still feels very slow, but I haven't timed anything; could it be that it had the effect of keeping the IRQ functional after all, but 5.0-rc6 is slower than earlier kernels for other reasons? Like, /proc/irq/14/pata_cs5536/ is there, but I haven't checked whether it was there before the patch. Do you suggest any way to tell whether it had the intended effect? -- Alexandre Oliva, freedom fighter https://FSFLA.org/blogs/lxo Be the change, be Free! FSF Latin America board member GNU Toolchain Engineer Free Software Evangelist Hay que enGNUrecerse, pero sin perder la terGNUra jamás-GNUChe
