CHABAL David wrote: > Le 11/5/2007, "Jan Kiszka" <[EMAIL PROTECTED]> a écrit: > >> Maksym Veremeyenko wrote: >>> CHABAL David пишет: >>> >>>> I met some trouble with the 16550A driver provided in Xenomai 2.3.1 >>>> and my Moxa cards (PCI / 8 * RS232 / 168U ). >>>> >>>> It was a problem of baudrate computation before setting the LCR_DLAB >>>> register. >>>> >>>> The formula implemented by the Xenomai driver is different from the one >>>> provided by Moxa. So I copy/paste the formula from the mxser.c file >>>> (present in the >>>> kernel distro), and it seems to work fine. >>>> >>>> I think it's Moxa card dependant, may be caused by the high default baud >>>> rate of this card. >>> I have two Moxa boards with no problem, possible you need to specify >>> 'baud_base' param. >>> >>> I my case : >>> >>> # 8 ports board: >>> /sbin/modprobe xeno_16550A \ >>> ioaddr=0x1000,0x1008,0x1010,0x1018,0x1020,0x1028,0x1030,0x1038 \ >>> irq=9,9,9,9,9,9,9,9 \ >>> baud_base=921600,921600,921600,921600,921600,921600,921600,921600 >>> >>> # 2 ports board + onboards: >>> /sbin/modprobe xeno_16550A ioaddr=0x3f8,0x2f8,0xdf00,0xdf08 >>> irq=4,3,11,11 baud_base=115200,115200,921600,921600 >>> >> Interesting. That would leave us just with the generic fix to catch >> baud_rate==0. Far more attractive. :) >> >> David, can you confirm this? Weren't you just aware of the baud_base >> parameter? > > I'm not totally convinced because if I compute by hand the DLAB register > with the 19200 value (my config): > > With the moxa driver: > baud_div = 912.600 / 19.200 = 47 > > With the Xeno driver: > baud_div = (912.600 - 9600) / 19.200 = 47 > > Grrr, it's ok here because the rounded values are the same because the > baud base is biggest than the speed requested, but I think a problem can > occur with 115200 or more, example: > > moxa: 912.600/115.200 = 8 > xeno: = 7
Yeah, hard arguments. This really cries for a moxa tweak. (The alternative would be to pass an artificially increased baud_base - but that would be _really_ ugly and we could also ask the user for the divider directly...) Jan
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