On Tuesday 27 March 2007 10:43 am, Pete Zaitcev wrote: > On Tue, 27 Mar 2007 14:30:52 +0200, Oliver Neukum <[EMAIL PROTECTED]> wrote: > > > --- a/drivers/usb/serial/option.c 2007-03-27 13:31:04.000000000 +0200 > > Why don't you just use kmalloc here? The needless use of usb_buffer_alloc > always irritates me. It's as if the iommu space is free and endless. > > We have tons of this crap all over the USB stack and I cannot understand > just why we keep doing this. Even printer and HID now got into the game. > Crazy!
Actually, HID was one of the original motivations for using that. Dave Miller noticed the cost for a USB keyboard was excessive on (ISTR) SPARC64, and avoiding all those cache ops was a Good Thing. Now, printers seem a clear case of where that should NOT be used. ISTR that isochronous transfers were discussed as potentially a good use of those no-cache-ops buffers. It's not clear to me that serial lines would be inappropriate; what guideline are you thinking of, to suggest they would be? Mostly when I use a serial line it's with a TTY emulator, so it's gota data rate someone less than a USB keyboard (one byte per character, vs several bytes of report) in one direction, and not much more in the other direction. So on that bases it would make the same sense HID makes. But I know some folk use serial lines more aggressively, which is why it's not clear to me one way or the other. - Dave ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
