> Date: Wed, 17 Aug 2016 15:38:39 +0200 > From: Marcus Glocker <mar...@nazgul.ch> > > If a FIFO device already got a FIFO depth assigned, don't run a FIFO > probe against it. > > ok?
Sorry, but no. As far as I understand, the FIFO probe was added to detect buggy 16550 versions that implement a FIFO that is one byte short. In this case, sc_fifolen is set to 16, bet then overriden by the probed depth: com0 at isa0 port 0x3f8/8 irq 4: ns16550a, 16 byte fifo com0: probed fifo depth: 15 bytes Your diff would break that. > Index: dev/ic/com.c > =================================================================== > RCS file: /cvs/src/sys/dev/ic/com.c,v > retrieving revision 1.159 > diff -u -p -r1.159 com.c > --- dev/ic/com.c 16 Aug 2016 08:15:04 -0000 1.159 > +++ dev/ic/com.c 17 Aug 2016 13:31:47 -0000 > @@ -1855,7 +1855,7 @@ com_fifo_probe(struct com_softc *sc) > u_int8_t fifo, ier; > int timo, len; > > - if (!ISSET(sc->sc_hwflags, COM_HW_FIFO)) > + if (!ISSET(sc->sc_hwflags, COM_HW_FIFO) || sc->sc_fifolen) > return; > > ier = 0; > >
