[LAU] midi triggering delay

[david]

andy baxter wrote:
> James Cameron wrote:
>> On Tue, Sep 08, 2009 at 07:17:30PM -1000, david wrote:
>>  
>>> USB not sharing interrupts with anything?
>>>     
>>
>> Andy's original post contained /proc/interrupts which showed some
>> sharing was happening.  Here's a cut:
>>
>>  16:     380396     233180   IO-APIC-fasteoi   uhci_hcd:usb4, yenta
>>  17:     829711     532117   IO-APIC-fasteoi   uhci_hcd:usb5, 
>> ohci1394, HDA Intel
>>  18:          0          0   IO-APIC-fasteoi   mmc0
>>  19:          2          0   IO-APIC-fasteoi   ehci_hcd:usb6
>>  20:         18         17   IO-APIC-fasteoi   uhci_hcd:usb1
>>  21:          0          0   IO-APIC-fasteoi   uhci_hcd:usb2
>>  22:     305246     302929   IO-APIC-fasteoi   ehci_hcd:usb3
>>
>> Sharing interrupts adds a tiny delay to interrupt handling; if this has
>> truly become significant, there's a design issue somewhere else.
>>
>> (Shared interrupts with modern kernels are not a huge problem, since the
>> drivers check to see if the interrupt they have is legitimate before the
>> kernel chains on to the next driver.  It's the waste of that additional
>> check that people want to avoid.)
>>
> The usb port I'm using is on INT 21 (uhci_hcd:usb2), which doesn't share 
> with anything.

Hmmm. Which video driver are you using (maybe you already mentioned it)? 
If using Intel, try VESA, or viceversa, just in case it's the video 
driver doing something?

-- 
David
gnome at hawaii.rr.com
authenticity, honesty, community