On Fri, 12 Mar 2010 15:57:44 +0000, Trifle Menot <triflemenot@xxxxxxxxxx> wrote: >If I start dosemu -s with this: > >> $_ports = "fast range 0x3F8,0x3FF" >> $_irqpassing = "4" > >A speed of 57600 looks fast, like it should be. But if I omit the >direct hardware access, and try this: > >> $_com1 = "/dev/ttyS0 irq 4" > >57600 still works, but looks much slower on the remote side of a null >modem cable. Seems like I read where the code traps serial port writes >and buffers data to /dev/ttyS0. Is the trapping causing the slowdown? >Is there a cure? Digging deeper, I noticed that my PCBoard BBS recognized a 16550 when using direct hardware access, but only a 16450 with /dev/ttyS0. I looked at the dosemu source to try and understand why. Being new to the code, I'm not 100% sure of what I'm saying here, but it looks like FIFO mode is turned on according to whatever bits are poked into the virtual UART. So then I looked closer my PCBoard configuration, and I noticed a setting to "Force 16550A usage" and I turned it on. With that setting, PCBoard now sees a 16550 when using /dev/ttyS0, and my remote output looks fast, like 57600 should. So poking the necessary bits into the dosemu virtual UART fixed things up. -- Web mail, POP3, and SMTP http://www.beewyz.com/freeaccounts.php -- To unsubscribe from this list: send the line "unsubscribe linux-msdos" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
