Re: [PARPORT] Buffer read/write verification

Philip Blundell (
Fri, 19 Mar 1999 16:47:44 +0000

>That assumes the philosophy of copying buffers around. I'm dealing with images
>which would require copying buffers of up to 256k in size. Its bad enough

If you're dealing with 256k of data the overhead of set_fs() is negligible. I
agree it's not ideal that you have to do this but the alternative would be to
force any driver that *does* want to supply data from user space (eg, lp) to
bounce it through a kernel buffer.

>>The bulk of the parport calls should resolve down to single "asm" statements,
>>at least for the port access level.

>Not for IEEE1284 support, I'm afraid. If only!!! There's often a load of bit
>twiddling and handshaking of control lines before a byte of data changes

It might possibly be worth investigating the idea of providing "fast path"
IEEE1284 functions for at least the common cases.


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This archive was generated by hypermail 2.0b3 on Sun 28 Mar 1999 - 17:02:35 EST