Re: [patch] 2.4.0-test6-pre8: Magic SysRq fixes for serial.c

From: Maciej W. Rozycki (macro@ds2.pg.gda.pl)
Date: Wed Aug 09 2000 - 11:31:29 EST

On Wed, 9 Aug 2000, Theodore Y. Ts'o wrote:

> Break is *not* an asynchoronous event. (It means that the RX line has
> been pulled low for some period of time). The BI is only raised when
> the associated null character in the FIFO is revealed at the top of the
> FIFO. This is the standard behaviour defined by the 16550 UART, and any
> clones which gets this wrong are broken.

 Thanks for the clarification. Certain chips handle it differently, for
example Zilog's 8530 asserts a BREAK interrupt as soon as a BREAK
condition is detected (regardless of other events), then when the BREAK
condition is removed it asserts a BREAK-deassert interrupt, after which a
null character is available (with a respective data interrupt). 

-- 
+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+--------------------------------------------------------------+
+        e-mail: macro@ds2.pg.gda.pl, PGP key available        +

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

This archive was generated by hypermail 2b29 : Tue Aug 15 2000 - 21:00:18 EST