On Mon, 1 Mar 2010, Albert Herranz wrote:
If transfer_buffer_length is 0 then do nothing.
Otherwise if num_sgs 0 then do nothing.
Otherwise if URB_NO_TRANSFER_DMA_MAP and transfer_dma
are both set (this avoids your HCD_NO_COHERENT_MEM
case) then do
Alan Stern wrote:
On Mon, 1 Mar 2010, Albert Herranz wrote:
If transfer_buffer_length is 0 then do nothing.
Otherwise if num_sgs 0 then do nothing.
Otherwise if URB_NO_TRANSFER_DMA_MAP and transfer_dma
are both set (this avoids your HCD_NO_COHERENT_MEM
On Tue, 2 Mar 2010, Albert Herranz wrote:
Currently this URB doesn't require PIO is always true, but in the
future it won't be.
Can this be currently tested?
Not yet, but soon. You can follow the gory details in this email
thread:
On Sun, 28 Feb 2010, Albert Herranz wrote:
The HCD_NO_COHERENT_MEM USB host controller driver flag can be enabled
to instruct the USB stack to avoid allocating coherent memory for USB
buffers.
This flag is useful to overcome some esoteric memory access restrictions
found in some platforms.
Alan Stern wrote:
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1260,6 +1260,34 @@ static void hcd_free_coherent(struct usb_bus *bus,
dma_addr_t *dma_handle,
*dma_handle = 0;
}
+static int urb_needs_setup_dma_map(struct usb_hcd *hcd, struct urb *urb)
+{
+
On Mon, 1 Mar 2010, Albert Herranz wrote:
Also, I can't help thinking that the corresponding *_map() and
*_unmap() routines are so similar, it ought to be possible to combine
them. The only difference is a check for a NULL DMA address, and it's
not clear to me why it is present. It's
Alan Stern wrote:
If urb-num_sgs 0 then urb has been s-g mapped. Although we don't
currently check for it, quite a few URBs have transfer_buffer_length ==
0 (a number of control requests are like this, for example) so they
don't need a mapping either.
Ok, I'll use urb-num_sgs 0 to check
On Mon, 1 Mar 2010, Albert Herranz wrote:
Am I on the right path?
More or less. I would do it somewhat differently:
If URB_NO_TRANSFER_DMA_MAP is set then no map is needed.
Otherwise if num_sgs 0 then no map is needed.
Otherwise if HCD_NO_COHERENT_MEM is set then use
Alan Stern wrote:
On Mon, 1 Mar 2010, Albert Herranz wrote:
Am I on the right path?
More or less. I would do it somewhat differently:
If URB_NO_TRANSFER_DMA_MAP is set then no map is needed.
Otherwise if num_sgs 0 then no map is needed.
Otherwise if HCD_NO_COHERENT_MEM is
