Hi,
I have a question related to the consistent memory in the USB OHCI driver. Maybe the question is already answer on the mailing list archive, but I did not find where.
It's probably at the top of (2.6) drivers/usb/host/ohci-mem.c ...
I notice that sometime the buffer give to the TD is not allocated in consistent memory. Ex: in the usb.c: usb_control_msg(), kalloc is called using the GFP_KERNEL only.
That particular memory gets DMA-mapped later. Some drivers will want to allocate dma-coherent memory themselves, to cut down on some type of overhead (like IOMMU thrashing).
- Dave
This buffer is fillup with the request. After the buffer is given to the appropriate TD in order to start the transfer.
My question is, why this buffer is not in consistent memory? Is it because it is a SETUP or an OUT message? If yes, That mean only inbound messages need buffer in consistent memory? Am I right??
Anwsering that question will help me exposing my real problem.
Thanks
Etienne
------------------------------------------------------- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
