serial 8250, sysrq, and break

From: Kumar Gala
Date: Mon Feb 19 2007 - 17:45:49 EST


I'm trying to figure out if an issue I'm having with sysrq (more likely with receiving a BREAK) is a HW issue or software.

If I have a lot of spew in the kernel (like a printk in receive_chars ()) sysrq seems to work properly, in that the character sent after the break is properly received. However, if I don't have any spew the character after the break than I get the wrong character:

[ 22.607920] SysRq : in __sysrq_get_key_op key:255
[ 34.856712] SysRq : in __sysrq_get_key_op key:255
[ 44.823519] SysRq : in __sysrq_get_key_op key:252
[ 51.306161] SysRq : in __sysrq_get_key_op key:240
[ 60.947047] SysRq : in __sysrq_get_key_op key:252
[ 65.942674] SysRq : in __sysrq_get_key_op key:128
[ 102.251461] SysRq : in __sysrq_get_key_op key:254

It seems like hw is treating part of the break as a valid received character. But, wanted to see if there were any ideas before I consider this a HW issue.

- k
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