re your change to the low_latency flag in the hso driver in 2.6.29-rc1
From: Denis Joseph Barrow <hidden>
Date: 2009-01-12 17:23:57
Hi Alan, I remember removing the low_latency flag to 0 once & if I recall correctly performance was severely impacted & there may have been other problems which I don't recall. even worse I believe the code can now hang the kernel, the fix is simple, in put_rxbuf_data I'm dependent on the TTY_THROTTLED bit to exit the loop. Now tty_insert_flip_string can return 0 bytes leading to an infinite loop if tty buffers are full, as write_length_remaining never goes to zero as I am dependent on the line discipline being called from tty_flip_buffer_push to set TTY_THROTTLED by calling flush_to_ldisc checking if curr_write_len=0 from tty_insert_flip_string might fix the problem Please look at put_rxbuf_data carefully, there might be other gremlins. The serial port is supposed to be high performance this fix will impact this -- best regards, D.J. Barrow Linux Kernel Developer Option NV, Gaston Geenslaan 14, 3001 Leuven, Belgium T: +32 16 311 621 F: +32 16 207 164 d.barow@option.com www.option.com Disclaimer: http://www.option.com/company/disclaimer.shtml