At Wed, 30 Apr 2008 22:07:42 +0200, Pavel Hofman wrote:
Takashi Iwai wrote:
At Fri, 25 Apr 2008 09:06:19 +0200, Pavel Hofman wrote:
Takashi Iwai wrote:
I do not know the reason for MPU401_INFO_NO_ACK. You removed it from the original patch, but without it I always get the input/output error.
Ah, thanks, I overlooked it. Fixed now.
Takashi, thanks, but the patch I sent you sets MPU401_INFO_INPUT and MPU401_INFO_OUTPUT flags too. They enable the actual input/output methods in mpu401_uart.c.
They aren't needed if you create full-duplex streams. Could you check whether the latest code still causes any errors?
The code works fine on standard kernel.
But in the RT kernel of Ubuntu 7.10 (2.6.22-14-rt, 1000HZ compared to 250HZ of the -generic kernel), MIDI interrupts get thrown continuously, hogging CPU with the IRQXX "process".
When playing 44.1kHz audio with buffer size of 32768, snd_vt1724_interrupt is called every 185ms. With the buffer size of 4096, it is every 23ms. So far so good.
But when I try to output some midi, the routine gets called every 24us (i.e. 1000 times faster). Comparing the time difference between my several debug printk's in snd_vt1724_interrupt (approx. 5us between each printk record a few lines of code apart) and between each call of the method (24us), I thought there would be a loop somewhere in the interrupt handler calling code. But /proc/interrupts really shows over 40k interrupts a second for ICE1724.
Changing the watermarks up to 0x1f makes no difference.
That looks bad.
Masking the MIDI interrupts works, snd_vt1724_interrupt is called only during VT1724_IRQ_MTPCM interrupts, with the MIDI status bits MPU_TX/MPU_RX set when reading/writing with amidi.
Hm, is it TX or RX, or in both cases? Could you check which one (TX or RX) causes this?
Takashi
My HW: ancient AMD Duron 900MHz.
The interrupt flood occurs no matter whether the MIDI input is connected to my MIDI keyboard or not.
Thanks a lot to anyone for suggestions.
Pavel.