On Thu, 2015-10-08 at 13:28 +0100, Daniel Thompson wrote: > On 08/10/15 13:05, chunfeng yun wrote: > > Hi, > > On Thu, 2015-10-01 at 12:44 +0100, Daniel Thompson wrote: > >> On 29/09/15 04:01, Chunfeng Yun wrote: > >>> There some vendor quirks for MTK xhci host controller: > >>> 1. It defines some extra SW scheduling parameters for HW > >>> to minimize the scheduling effort for synchronous and > >>> interrupt endpoints. The parameters are put into reseved > >>> DWs of slot context and endpoint context. > >>> 2. Its IMODI unit for Interrupter Moderation register is > >>> 8 times as much as that defined in xHCI spec. > >>> 3. Its TDS in Normal TRB defines a number of packets that > >>> remains to be transferred for a TD after processing all > >>> Max packets in all previous TRBs. > >>> > >>> Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx> > >> > >> I've done some basic soak tests, both with a directly attached USB3 HDD > >> and, given the extra code to manage isochronous xfer, also with a hub, > >> disc and two audio interfaces. > >> > >> Tested-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx> > >> > >> > >>> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c > >>> index 57f40a1..243f696 100644 > >>> --- a/drivers/usb/host/xhci-ring.c > >>> +++ b/drivers/usb/host/xhci-ring.c > >>> @@ -68,6 +68,7 @@ > >>> #include <linux/slab.h> > >>> #include "xhci.h" > >>> #include "xhci-trace.h" > >>> +#include "xhci-mtk.h" > >>> > >>> /* > >>> * Returns zero if the TRB isn't in this segment, otherwise it returns the DMA > >>> @@ -3044,18 +3045,27 @@ static u32 xhci_td_remainder(struct xhci_hcd *xhci, int transferred, > >>> struct urb *urb, unsigned int num_trbs_left) > >>> { > >>> u32 maxp, total_packet_count; > >>> + u32 skip_current_trb = 0; > >> > >> A bit of a nitpick but why do we need skip_current_trb? Testing > >> (xhci->quirks & XHCI_MTK_HOST) twice would make what the code does, and > >> why, more obvious. > >> > > I am not sure which way it is better, so add variable of > > skip_current_trb to reduce test times. > > I can't imagine either approach impacts performance. However introducing > skip_current_trb makes the flow of the branches harder to follow. > > The first branch was a version check and can remain so; we only need to > do something special with the quirks because the MTK controller is 0.97 > but with a few bits added: > > /* MTK xHCI is mostly 0.97 but contains some features from 1.0 */ > if (xhci->hci_version < 0x100 && !(xhci->quirks & XHCI_MTK_HOST)) > return ... > > Setting trb_buff_len to zero is accommodating a quirk and this is > clearer when we have: > > /* for MTK xHCI, TD size doesn't include this TRB */ > if (xhci->quirks & XHCI_MTK_HOST) > trb_buff_len = 0; > I will revise the code according to your suggestion, thanks > > >> Anyhow with that looked at, and the caveat that I'm not much of USB > >> expert, you're welcome to add my Reviewed-by: to v10. > >> > > > > Thanks a lot > > No worries. > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html