diff options
| author | Mathias Nyman <mathias.nyman@linux.intel.com> | 2021-06-17 18:03:52 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-06-17 17:34:29 +0200 |
| commit | 90d551a5bc73d34c600507a1ef61f3a7c0840783 (patch) | |
| tree | b96536551e298ebd0d6f7fed5a5249908cce137a /drivers/usb/host/xhci.h | |
| parent | ebd88cf50729e1891dbd307dec311b8f05ba2462 (diff) | |
xhci: Add adaptive interrupt rate for isoch TRBs with XHCI_AVOID_BEI quirk
Save a bit of power by not interrupting so often by default if
XHCI_AVOID_BEI quirk is set.
In normal cases the xhci driver will only generate an interrupt on the last
isochronous TRB of an URB. In a common UVC webcam usecase there are 32 TRBs
per URB.
if AVOID_BEI flag is set then xhci driver will force an interrupt every 8th
isoc TRB to make sure the event ring doesn't get too full.
This is however way too frequent in common single webcam use cases, causing
1000 interrupts/sec and thus poor powermanagement performance.
Instead start with interrupting every 32 isoc TRB, and halve it in case
event ring becomes half-full. Stop halving when reaching a rate of every
8th trb.
This is a one way solution. If interrupt rate is increased it will stay
high until driver is reloaded. The highest rate is the same as the old
default rate.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210617150354.1512157-3-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/host/xhci.h')
| -rw-r--r-- | drivers/usb/host/xhci.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index 85ba326806ab..5ba01d5ccab8 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1526,6 +1526,12 @@ static inline const char *xhci_trb_type_string(u8 type) #define TRB_BUFF_LEN_UP_TO_BOUNDARY(addr) (TRB_MAX_BUFF_SIZE - \ (addr & (TRB_MAX_BUFF_SIZE - 1))) #define MAX_SOFT_RETRY 3 +/* + * Limits of consecutive isoc trbs that can Block Event Interrupt (BEI) if + * XHCI_AVOID_BEI quirk is in use. + */ +#define AVOID_BEI_INTERVAL_MIN 8 +#define AVOID_BEI_INTERVAL_MAX 32 struct xhci_segment { union xhci_trb *trbs; @@ -1768,6 +1774,7 @@ struct xhci_hcd { u8 isoc_threshold; /* imod_interval in ns (I * 250ns) */ u32 imod_interval; + u32 isoc_bei_interval; int event_ring_max; /* 4KB min, 128MB max */ int page_size; |