Messages in this thread | | | Date | Wed, 1 Sep 1999 11:36:44 -0400 | From | "Theodore Y. Ts'o" <> | Subject | Re: PATCH: Update for the serial driver. |
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Date: Wed, 1 Sep 1999 16:46:56 +0200 (MEST) From: R.E.Wolff@BitWizard.nl (Rogier Wolff)
Theodore, May I ask for a "name" field in your PCI-table? Then we can say something like "Detected an xxxx card". That make supporting such a card a lot easier: People get reassured that their card got detected.
The reason why I haven't done this is because I don't want to bloat the kernel with overly large tables; if past history is any guide, I have no doubt that the number of PCI serial boards will be *large*.
If we are going to be doing this, we should use the same mechanism of mapping vendor/device id's to (string) names that is used in drivers/pci/oldproc.c. But some poeple have wanted to phase this out entirely, although I think I remember a comment from Linus that he thinks it might be good for that functionality to stay in the kernel.
So we should settle the larger-scale issue of should the kernel take up in-kernel memory that maps PCI id's to names in general first, IMHO.
We can certainly add a message saying that "PCI serial card 1415:9501 detected". Would that solve your issue.
The Speed4 card is equipped with line drivers capable of 115k2, not more. It would be best to disable (by default) the "clock multiplier modes" of the 16PCI954/16C950. Or at least warn that this exceeds specs for the card. (I'm pretty sure that you won't blow anything up, as the Xfree team is afraid about....)
What happens when you exceeds the specs for the card? Is it like what happens when you overclock a Celeron? (i.e., nothing bad happens most of the time. :-) I'll note that most people exceed the original RS-232 standard's cable length specifications at the higher baud rates, and usually nothing bad happens. Part of this is because cables are higher quality than the original RS-232 specification surmised, and part of it was the standard was fairly conservative.
If there's no danger to the hardware, my first thought is that it's not worth the complexity to prevent it from happening, since then you'll need to add an override mechanism, and that adds even more complexity....
- Ted
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