Messages in this thread | | | Date | Wed, 9 Aug 2000 18:31:29 +0200 (MET DST) | From | "Maciej W. Rozycki" <> | Subject | Re: [patch] 2.4.0-test6-pre8: Magic SysRq fixes for serial.c |
| |
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/
| |