From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ross Boylan Subject: Re: Update on problems with UPS Date: Thu, 27 Feb 2003 12:42:55 -0800 Sender: linux-serial-owner@vger.kernel.org Message-ID: <20030227204255.GF5806@wheat.boylan.org> References: <20030221063220.GF5567@wheat.boylan.org> <20030223080137.GB374@lafn.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20030223080137.GB374@lafn.org> List-Id: linux-serial@vger.kernel.org To: linux-serial@vger.kernel.org Cc: Ross Boylan Thank you for all this useful information. I'm not sure I followed all of it, so I want to clarify a couple of points. I talked about pnp reseting the modem or the serial port on the card. You say it would only affect the port. What I had in mind was that pnp might reset the IRQ for one device, but not the other, so they wouldn't be able to communicate. Are you saying that's so? I think what you mean is that only the serial port needs an IRQ, since the modem talks to the serial port talks to the computer. So regardless of how I set pnp, the serial port and modem will be able to communicate. Correct? Further, the reason I lose communication with the port/modem after manually running pnp is that the serial driver does not know that the port has moved. If I manually change the IRQ with pnp, I need to manually tell the driver with setserial. Correct? Thanks. On Sun, Feb 23, 2003 at 12:01:37AM -0800, David Lawyer wrote: > On Thu, Feb 20, 2003 at 10:32:20PM -0800, Ross Boylan wrote: > > I wrote a few weeks ago about some problems using an APC UPS with the > > serial port. > > > > I've made some progress, but things are still not quite working right. > > > > Originally, I got "LSR safety check engaged" on ttyS1 where the APC > > was connected. This went away when I disabled COM1 (aka ttyS0) in > > BIOS, since I no longer use it. However, I am still sharing an IRQ > > between ttyS2 (from my ISA modem card) and the parallel printer. > > > > It's not clear the sharing is causing trouble--both seem to be working > > OK. Does anyone know if it's a problem? > It may cause a problem if you are printing while using the modem. > > > > At any rate, it is puzzling to me that I can't control the IRQ for the > > modem. Only COM1/2 are configurable from BIOS. I can also control > > the parallel port from the BIOS, and I though putting it to IRQ5 would > > force COM3 elsewhere. It doesn't seem to. > Some devices can only be set to a limited number of IRQs and all > possibilities may cause a conflict so it may use one of these conflicts: > IRQ5 > > > I can reprogram the modem through isapnp, but unless I put it to the > > IRQ 5 that ttyS2 gets on startup, it doesn't work. (Some people > > suggested the card might be set through jumpers, but it's not). I've > > also tried restarting after reprogramming the modem, in hopes the new > > IRQ would stick, but it doesn't. > > That's right. PnP resources such as IRQs set in a device disappear when > powered down. You've got to run setserial to tell the serial driver > what you set with isapnp. Another way to get it to work is to setserial > to IRQ0 which will use the serial port using inefficient polling, but it > still should work. > > > Can anyone clarify what is going on with COM3? I thought the modem > > serial port was actually part of the card, and that reseting the card > > through pnp would change the modem and the serial port. The behavior > > I'm seeing looks more like the serial port and the modem are distinct > > devices > Yes but the modem is not listed in /dev so it's not a device in that > sense. > > >, and pnp only affects the modem. > > It only affects the serial port on the modem card. > > > (My other theory is that pnp affects both, > It only affects the serial port. > > but the serial driver doesn't know what's going on if I move the > > location after startup. > Correct > > This would also explain why the modem doesn't work after I move the > > IRQ, > Correct > > but I thought I understood someone on this list saying the serial > > driver could cope with such moves.) > > Well, it can if it uses its own isapnp to set the IRQ but you explicitly > ran isapnp. > > > [snip about UPS as I know almost nothing about them] > David Lawyer > - > To unsubscribe from this list: send the line "unsubscribe linux-serial" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html