Messages in this thread | | | Date | Sun, 02 Dec 2012 19:26:27 +0200 | From | Eli Billauer <> | Subject | Re: [PATCH 2/2] New driver: Xillybus generic interface for FPGA (programmable logic) |
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On 11/30/2012 06:32 PM, Greg KH wrote: >>>> > >>+static struct class *xillybus_class; >>>> >>> > >Why not just use the misc interface instead of your own class? >>> >> > When Xillybus is used, the whole system's mission is usually around >> > it (e.g. it's a computer doing data acquisition through the Xillybus >> > pipes). So giving it a high profile makes sense, I believe. Besides, >> > a dozen of device files are not rare. >> > It is no problem to create dozens of misc devices. It makes your driver > smaller, contain less code that I have to audit and you have to ensure > you got right, and it removes another user of 'struct class' which we > are trying to get rid of anyway. So please, move to use a misc device. > >
It has just occurred to me that DYNAMIC_MINORS is 64 (drivers/char/misc.c), so I guess that limits the number of misc devices that can be generated, at least with dynamically allocated minors. I previously mentioned "a dozen" as the number of devices, but I've already run tests with 100+ devices, and I can also think of a sane application for that.
So if I understood the situation correctly, it looks like using misc devices will create a limitation which will be reached sooner or later.
Any suggestion what to do?
Thanks in advance,
Eli
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