From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lucio De Re To: 9fans@cse.psu.edu Subject: UART device driver (Was: [9fans] random moving of cursor arrow) Message-ID: <20030725163518.Z28024@cackle.proxima.alt.za> References: <07e062e5bb237e12823dad2438110d9a@plan9.escet.urjc.es> <20030725140808.12243.qmail@g.bio.cse.psu.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20030725140808.12243.qmail@g.bio.cse.psu.edu>; from Scott Schwartz on Fri, Jul 25, 2003 at 10:08:08AM -0400 Date: Fri, 25 Jul 2003 16:35:19 +0200 Topicbox-Message-UUID: 040c8680-eacc-11e9-9e20-41e7f4b1d025 On Fri, Jul 25, 2003 at 10:08:08AM -0400, Scott Schwartz wrote: > > When doing a pull over ppp, eia1status reports lots of overruns. Watching > the modem lights it looks like CS is always lit (not so under linux.) > So I think something is not quite right in the uart driver. There's been a rewrite since 3rd Ed (you may recall lack of serial mouse support when 4th Ed was first released), and I had already noted bad mouse response on an AMD 586 wanna-be, but recently a faster CPU started showing signs of stress. At a glance, the interupt handler does not seem bloated, but I haven't had a chance to compare different versions. I understand this is Presotto territory so we may have to wait for his return. I'll have alook around in the meantime, the 8250 is one chip I understood pretty well in my day. The FIFO adds a little complexity I have not yet explored, but I don't think it's excessive. I have a vested interest, anyway: I have a six-port BOCA card with the most creative way of mapping its six ports to the I/O and interrupt space and I'd like some suggestions on representing this in plan9.ini. For each port, I can specify one of two addresses, where the first four may map to the conventional 3F8, 2F8, 3E8 and 2E8 of COM1, 2, 3 and 4 of yore. 3E0 and 2E0 are the options for the last two. The alternatives are 220, 228, 240, 248, 260, 268 (all hex, of course). I think I can disable a port by leaving out the corresponding jumper, too. Then for each port I have a choice of IRQ 4, 3, 10, 11, 12 and 15, respectively, or I can choose SHARED for any or all of them. Shared, in turn, can be IRQ 4 or 5. I'm looking for a way to indicate each of these options in plan9.ini, keeping in mind that I may want to use the default eia0 and eia1 (I don't know how far these stretch, given that on the original PC COM3 and COM4 uncomfortably shared IRQ$ and IRQ3 with COM1 and COM2, respectively). I thought of a six-character string like 112200 with 1 for IOP option 1, 2 for option 2 and 0 for disabled, but it's ugly and still does not help with shared IRQs. I won't mind using six description lines, but I don't know the plan9.ini syntax scanner well enough to implement such a thing without some advice. ++L PS: One last question, how would I handle a USB modem? Will I have to provide my own support?