Messages in this thread | | | Date | Wed, 22 May 2002 11:57:40 -0700 | From | "Maksim (Max) Krasnyanskiy" <> | Subject | Re: [linux-usb-devel] Re: What to do with all of the USB UHCI drivers in the kernel ? |
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At 09:33 PM 5/21/2002 -0700, David Brownell wrote: >Maksim (Max) Krasnyanskiy wrote: >>One-shot interrupt transfers are broken in *-hcd drivers. core/hcd.c >>returns EINVAL if urb->interval==0. ><....> >Meanwhile, I suppose I can see wanting access to that UHCI-ism. >However your patch would do that wrong, since it should only >apply to interrupt transfers. Yeah, I guess it doesn't make sense to do one-shot iso.
>>On a side note. Why are URBs still not SLABified ? > >Hasn't seemed to be necessary. kmalloc() is slabified already, >so it's not clear that a control/bulk/interrupt URB pool shared >between drivers -- size, maybe a handful -- would be better than >sharing that same memory with other kernel code. Well, kmalloc has slabs of a fixed size and will round requested amount to the nearest value. For example on x86 sizeof(struct urb) == 84 which will be rounded to 96 by kmalloc ie 12 bytes unused (on Sparc64 it's about 20 bytes). Also we could use slab constructor to pre-initialize some urb fields.
Max
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