[LAU] 1. Linux-Rt and TSC - 2. Linux-Rt and IRQ allocation

[Ralf Mardorf]

On Wed, 2014-01-22 at 18:56 +0100, Clemens Ladisch wrote:
> > 2. Linux-Rt and IRQ allocation
> > ==============================
> >
> > All kernels I used in the last years for *buntu, Debian and Arch Linux
> > <= 3.8.13-rt14 (kernels > 3.8.13-rt14 don't work on my machine) give my
> > graphics it's own IRQ, the Debian kernel 3.2.0-4-rt-686-pae doesn't.
> 
> What is difference in /proc/interrupts?

Hi Clemens,

Im not absolutely sure if the 3.2 kernels already gave the graphics it's
own IRQ on my machine, when I used them a long time ago, but AFAIR those
kernels already did, at least the IRQ was displayed by commands that
should show the IRQ, but now something is fishy.

The graphics even isn't listed in /proc/interrupts for the Debian
3.2.0-4-rt-686-pae. Today I build a 3.8.13-rt14-pae kernel that is ok.

rocketmouse at debi386:~$ uname -a
Linux debi386 3.8.13-rt14-pae-rocketmouse-2 #1 SMP PREEMPT RT Mon Jan 27 15:47:47 CET 2014 i686 GNU/Linux
rocketmouse at debi386:~$ /etc/init.d/rtirq status

  PID CLS RTPRIO  NI PRI %CPU STAT COMMAND	
   39 FF      90   - 130  0.0 S    irq/8-rtc0	
  644 FF      85   - 125  0.0 S    irq/18-snd_hdsp	
  646 FF      80   - 120  0.0 S    irq/20-snd_ice1	
  650 FF      79   - 119  0.0 S    irq/21-snd_ice1	
  631 FF      75   - 115  0.0 S    irq/19-ehci_hcd	
  632 FF      75   - 115  0.0 S    irq/16-ohci_hcd	
  634 FF      74   - 114  0.5 S    irq/17-ohci_hcd	
  649 FF      73   - 113  0.2 S    irq/17-ohci_hcd	
   38 FF      70   - 110  0.0 S    irq/1-i8042	
   27 FF      50   -  90  0.0 S    irq/9-acpi	
  126 FF      50   -  90  0.6 S    irq/22-ahci	
  569 FF      50   -  90  0.0 S    irq/7-parport0	
  621 FF      50   -  90  0.0 S    irq/22-firewire	
  623 FF      50   -  90  0.0 S    irq/43-radeon	
  625 FF      50   -  90  0.0 S    irq/14-pata_ati	
  626 FF      50   -  90  0.0 S    irq/15-pata_ati	
  642 FF      50   -  90  0.0 S    irq/18-ohci_hcd	
  651 FF      50   -  90  0.0 S    irq/18-ohci_hcd	
 1883 FF      50   -  90  0.0 S    irq/42-eth0	
    3 FF       1   -  41  0.1 S    ksoftirqd/0	
   15 FF       1   -  41  0.2 S    ksoftirqd/1	

rocketmouse at debi386:~$ ls /proc/irq/* | grep radeon
radeon
rocketmouse at debi386:~$ ls /proc/irq/43 | grep radeon
radeon
rocketmouse at debi386:~$ sudo lshw -c video | grep irq
resources: irq:43 memory:d0000000-dfffffff memory:fdff0000-fdffffff ioport:ce00(size=256) memory:fde00000-fdefffff

rocketmouse at debi386:~$ uname -a
Linux debi386 3.2.0-4-rt-686-pae #1 SMP PREEMPT RT Debian 3.2.51-1 i686 GNU/Linux
rocketmouse at debi386:~$ /etc/init.d/rtirq status

  PID CLS RTPRIO  NI PRI %CPU STAT COMMAND	
   36 FF      90   - 130  0.0 S    irq/8-rtc0	
  623 FF      85   - 125  0.0 S    irq/18-snd_hdsp	
  634 FF      80   - 120  0.0 S    irq/20-snd_ice1	
  638 FF      79   - 119  0.0 S    irq/21-snd_ice1	
  560 FF      75   - 115  0.0 S    irq/19-ehci_hcd	
  569 FF      75   - 115  0.0 S    irq/16-ohci_hcd	
  570 FF      74   - 114  0.0 S    irq/17-ohci_hcd	
  586 FF      73   - 113  0.0 S    irq/17-ohci_hcd	
   34 FF      70   - 110  0.0 S    irq/1-i8042	
   24 FF      50   -  90  0.0 S    irq/9-acpi	
  129 FF      50   -  90  0.3 S    irq/22-ahci	
  561 FF      50   -  90  0.0 S    irq/22-firewire	
  565 FF      50   -  90  0.0 S    irq/14-pata_ati	
  566 FF      50   -  90  0.0 S    irq/15-pata_ati	
  574 FF      50   -  90  0.0 S    irq/18-ohci_hcd	
  593 FF      50   -  90  0.0 S    irq/7-parport0	
  594 FF      50   -  90  0.0 S    irq/18-ohci_hcd	
 1855 FF      50   -  90  0.0 S    irq/42-eth0	
    3 FF       1   -  41  0.1 S    ksoftirqd/0	
   13 FF       1   -  41  0.1 S    ksoftirqd/1	

rocketmouse at debi386:~$ ls /proc/irq/* | grep radeon
rocketmouse at debi386:~$ sudo lshw -c video | grep irq
resources: irq:18 memory:d0000000-dfffffff memory:fdff0000-fdffffff ioport:ce00(size=256) memory:fde00000-fdefffff

Regards,
Ralf