Messages in this thread | | | Subject | Re: serial.c (modem-fcr) | Date | Wed, 27 Oct 1999 15:21:39 +0200 (MEST) | From | (Rogier Wolff) |
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Theodore Y. Ts'o wrote: > Date: Wed, 27 Oct 1999 09:01:46 +0200 (MEST) > From: kees <kees@schoen.nl> > > While I'm reading the datasheet for the (EXAR) ST16550, this is an uart > with fifo's, I'm beginning to believe that the serial driver should > maintain a copy of this write-only register. > I understand (from this info) that when bits that are programmed i.e. FIFO > RX or TX trigger level the others must be re-written or they will be > lost(reset). > > The contents of the FIFO Control Register (FCR) is recalculated each > time we need it in change_speed(); since it's relatively trivial to > recalculate it, there's no point in saving a copy of it somewhere.
By the way, the OX16C954 has a "readable FCR" register, that you can read to get the current value....
Roger.
-- ** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 ** *-- BitWizard writes Linux device drivers for any device you may have! --* "I didn't say it was your fault. I said I was going to blame it on you."
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