This patch (as1609) changes the way ehci-hcd uses the "Isochronous
Scheduling Threshold" in its calculations. Until now the code has
ignored the threshold except for certain Intel PCI-based controllers.
This violates the EHCI spec.
The new code takes the threshold into account always, removing the
need for the fs_i_thresh quirk flag. In addition it implements the
"full frame cache" setting more efficiently, moving forward only as
far as the next frame boundary instead of always moving forward 8
microframes.
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/host/ehci-hcd.c | 2 +-
drivers/usb/host/ehci-pci.c | 1 -
drivers/usb/host/ehci-sched.c | 12 ++++--------
drivers/usb/host/ehci.h | 1 -
4 files changed, 5 insertions(+), 11 deletions(-)
Index: usb-3.6/drivers/usb/host/ehci.h
===================================================================
--- usb-3.6.orig/drivers/usb/host/ehci.h
+++ usb-3.6/drivers/usb/host/ehci.h
@@ -193,7 +193,6 @@ struct ehci_hcd { /* one per controlle
unsigned has_amcc_usb23:1;
unsigned need_io_watchdog:1;
unsigned amd_pll_fix:1;
- unsigned fs_i_thresh:1; /* Intel iso scheduling */
unsigned use_dummy_qh:1; /* AMD Frame List table quirk*/
unsigned has_synopsys_hc_bug:1; /* Synopsys HC */
unsigned frame_index_bug:1; /* MosChip (AKA NetMos) */
Index: usb-3.6/drivers/usb/host/ehci-pci.c
===================================================================
--- usb-3.6.orig/drivers/usb/host/ehci-pci.c
+++ usb-3.6/drivers/usb/host/ehci-pci.c
@@ -103,7 +103,6 @@ static int ehci_pci_setup(struct usb_hcd
}
break;
case PCI_VENDOR_ID_INTEL:
- ehci->fs_i_thresh = 1;
if (pdev->device == PCI_DEVICE_ID_INTEL_CE4100_USB)
hcd->has_tt = 1;
break;
Index: usb-3.6/drivers/usb/host/ehci-hcd.c
===================================================================
--- usb-3.6.orig/drivers/usb/host/ehci-hcd.c
+++ usb-3.6/drivers/usb/host/ehci-hcd.c
@@ -503,7 +503,7 @@ static int ehci_init(struct usb_hcd *hcd
/* controllers may cache some of the periodic schedule ... */
if (HCC_ISOC_CACHE(hcc_params)) // full frame cache
- ehci->i_thresh = 2 + 8;
+ ehci->i_thresh = 0;
else // N microframes cached
ehci->i_thresh = 2 + HCC_ISOC_THRES(hcc_params);
Index: usb-3.6/drivers/usb/host/ehci-sched.c
===================================================================
--- usb-3.6.orig/drivers/usb/host/ehci-sched.c
+++ usb-3.6/drivers/usb/host/ehci-sched.c
@@ -1391,15 +1391,11 @@ iso_stream_schedule (
*/
if (likely (!list_empty (&stream->td_list))) {
- /* For high speed devices, allow scheduling within the
- * isochronous scheduling threshold. For full speed devices
- * and Intel PCI-based controllers, don't (work around for
- * Intel ICH9 bug).
- */
- if (!stream->highspeed && ehci->fs_i_thresh)
- next = now + ehci->i_thresh;
+ /* Take the isochronous scheduling threshold into account */
+ if (ehci->i_thresh)
+ next = now + ehci->i_thresh; /* uframe cache */
else
- next = now;
+ next = (now + 2 + 7) & ~0x07; /* full frame cache */
/*
* Use ehci->last_iso_frame as the base. There can't be any
--
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