On Thu, Feb 26, 2009 at 7:35 PM, Patrick Shirkey<pshirkey@xxxxxxxxxxxxxxxxx> wrote:> tizo wrote:>>>> Hi there,>>>> Sorry about my previous mail. I was just starting to write a draft>> about the topics I want to ask, and I accidentally push the send>> button.>>>> Well, my goal is to play two midi keyboards, sending the events>> through jackd, to qsynth. My computer is a Laptop HP 550, with HDA>> Intel sound card, 3 GB of memory, and a Core 2 DUO CPU of 1.40 GHz. My>> OS is UbuntuStudio 8.04, with kernel 2.6.24-23-rt.>>>> First of all, I cannot run jackd without xruns, if I configure it with>> 32 frames per period, or less. I am running it as root, with realtime,>> and a priority of 70. As soon as I run it, it starts to count xruns,>> and I am only executing jackd.>>>> Looking at the different IRQ, I have saw that my sound card is sharing>> the IRQ 16 with an USB port, and the video driver. This is a cat of>> /proc/interrupts:>>>> CPU0 CPU1>> 0: 1026591 1099066 IO-APIC-edge timer>> 1: 2060 839 IO-APIC-edge i8042>> 8: 0 1 IO-APIC-edge rtc>> 9: 121 95 IO-APIC-fasteoi acpi>> 12: 118454 56308 IO-APIC-edge i8042>> 14: 6410 5638 IO-APIC-edge libata>> 15: 5167 6228 IO-APIC-edge libata>> 16: 624 482 IO-APIC-fasteoi uhci_hcd:usb1, HDA>> Intel, i915@pci:0000:00:02.0>> 17: 24009 14458 IO-APIC-fasteoi eth1>> 18: 0 0 IO-APIC-fasteoi ehci_hcd:usb2,>> uhci_hcd:usb5>> 20: 0 0 IO-APIC-fasteoi uhci_hcd:usb3,>> ehci_hcd:usb6>> 21: 0 0 IO-APIC-fasteoi uhci_hcd:usb4>> 508: 378 139 PCI-MSI-edge eth0>> NMI: 0 0 Non-maskable interrupts>> LOC: 295845 239602 Local timer interrupts>> RES: 34174 96493 Rescheduling interrupts>> CAL: 10832 457 function call interrupts>> TLB: 873 742 TLB shootdowns>> TRM: 0 0 Thermal event interrupts>> THR: 0 0 Threshold APIC interrupts>> SPU: 0 0 Spurious interrupts>> ERR: 0>>>> I have searched a lot on Internet, and even in the list, and I have>> not found a way to change the IRQ assignments. In fact, I have read>> some mails that said that I can't do that in a laptop (except in some>> Thinkpads, where IRQ can be changed in the BIOS), as in PCs this can>> be done changing the card to other slot. In other places, some kernel>> parameters were suggested to obtain other IRQ assignments, but the>> only parameter that change those in my computer, was "acpi=off", and>> it was not better. In this case, /proc/interrupts shows the following:>>>> CPU0>> 0: 602 XT-PIC-XT timer>> 1: 209 XT-PIC-XT i8042>> 2: 0 XT-PIC-XT cascade>> 8: 0 XT-PIC-XT rtc>> 10: 2912 XT-PIC-XT uhci_hcd:usb1, uhci_hcd:usb3,>> uhci_hcd:usb4, ehci_hcd:usb6, eth1, HDA Intel, i915@pci:0000:00:02.0>> 11: 0 XT-PIC-XT ehci_hcd:usb2, uhci_hcd:usb5>> 12: 5196 XT-PIC-XT i8042>> 14: 9987 XT-PIC-XT libata>> 15: 704 XT-PIC-XT libata>> 508: 31 PCI-MSI-edge eth0>> NMI: 0 Non-maskable interrupts>> LOC: 87955 Local timer interrupts>> RES: 0 Rescheduling interrupts>> CAL: 0 function call interrupts>> TLB: 0 TLB shootdowns>> TRM: 0 Thermal event interrupts>> THR: 0 Threshold APIC interrupts>> SPU: 0 Spurious interrupts>> ERR: 0>>>> So, my first question is: is there a way to change my IRQ assignment?,>> or that really cannot be done in my laptop? I would like to have it in>> a not shared one, not necessarily in IRQ 9, as with rt kernel a>> priority raise of an IRQ can be done with chrt.>>>> Probably not. But check your bios anyway just in case you can reassign the> irq there.>> I had already checked that; it is not a possibility in my computer. >> I have also read, that the HDA sound card is not good for audio>> processing. I am just starting to configure my whole "synthetizer>> box", so by this time, I am only making some tests with it. But, for>> the near future, which usb sound card would you recommend?.>>>>>> The hda should give you reasonable audio quality and performance but you> will get better of both worlds with a professional sound card.>> Make sure it is usb-2.0 capable if you must use a usb sound card. You could> also look into a firewire device which tend to have better latency> performance.> Ok, thanks. >> I also wonder that, if the IRQ of USB ports cannot be change too, I>> would have some of them sharing some IRQ. Would that affect the>> performance, having an usb sound card?. And what about the performance>> of the midi events for the keyboards connected to the laptop?.>>>>>> If you can get the realtime kernel running it will improve latency> performance. But you might find that a standard kernel is good enough for> your general needs.>> Actually, I am using a realtime kernel. Anyway, I have to make somemore test with the midi keyboards. With one of them, I can play right,with 64 or 128 fpp, although there are some xruns. >> Thanks very much,>>>> tizo>> _______________________________________________>> Linux-audio-user mailing list>> Linux-audio-user@xxxxxxxxxxxxxxxxxxxx>> http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user>>>>> --> Patrick Shirkey> Boost Hardware Ltd.> Thanks, tizo_______________________________________________Linux-audio-user mailing listLinux-audio-user@xxxxxxxxxxxxxxxxxxxxxxxx://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
