Messages in this thread | | | Date | Wed, 14 Aug 2002 18:43:33 -0400 | From | JosMHinkle@netscape ... | Subject | Linux kernel 2.4.19 failure to access a serial port |
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Summary: In an i586 system with two serial ports and a modem, Linux fails to access the modem
Slight expansion: A system with two serial ports on ttyS0 and ttyS1 and a hardware modem on ttyS2 was not serviced properly in kernel 2.4.19 and some earlier ones. The modem at ttyS2 was fairly well ignored. The interrupt requests used were ttyS0:irq4 ttyS1:irq3 ttyS2:irq10
Temporary fix: In drivers/char/serial.c at the directive "#ifdef CONFIG_PCI" the assumption is made that interrupt requests are shared and there are more than four serial ports. That is not necessarily true, and the directives defeat the options set in configuration. The solution here was to comment out #define CONFIG_SERIAL_SHARE_IRQ and CONFIG_SERIAL_MANY_PORTS and recompile.
#ifdef CONFIG_PCI #define ENABLE_SERIAL_PCI /*** Commented out to allow unshared IRQ's on ttyS0-ttyS3 #ifndef CONFIG_SERIAL_SHARE_IRQ #define CONFIG_SERIAL_SHARE_IRQ #endif #ifndef CONFIG_SERIAL_MANY_PORTS #define CONFIG_SERIAL_MANY_PORTS #endif ***/ #endif
It seems a more sophisticated judgement needs to be made, and perhaps simply following the directions of the configurer would be advisable, in that these two items are made specifically available in configuration, and should not be silently bypassed.
Note: I have been informed the mailer here does not break lines as shown on the screen. I hope this message turned out better. It is purposely reposted so the viewer doesn't have to deal with the unbroken line version
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