Messages in this thread |  | | Date | Mon, 13 Jan 1997 21:54:15 -0500 | From | "Theodore Y. Ts'o" <> | Subject | Re: reserve= not working, drivers fail to do check_region |
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Date: Fri, 10 Jan 1997 10:32:34 +0100 From: Thomas Sailer <sailer@ife.ee.ethz.ch>
This as a very dangerous idea. There are currently drivers competing for the same hardware resource. For example the serial and the baycom drivers. When the serial driver gets loaded, it grabs all serial ports it finds. Now when someone afterwards loads the baycom driver and tells it to use a specific COM port, it would, using your idea, use this specific port and the serial driver would not know anything about that. This would result in two drivers trying to drive the same hardware with different ideas :-) There is now way the baycom driver can reliably detect if a baycom modem really sits at any specific COM port.
The serial driver only grabs reserves io regions and irq's for serial ports when the serial ports are actually open, and it checks to see if the ioports and irq's are available when the serial port is actually opened.
Thus, if a baycom driver is loaded, and grabs a COM port, the serial driver will return EBUSY when a attempt is made to open the COM port via the serial driver.
- Ted
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