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ITC (Interrupt Threshold Control) is used to set the maximum rate at which the host/device controller will issue interrupts. The default value is 8 (1ms) for it. EHCI core will modify it to 1, but device mode keeps it as default value. In some use cases like Android ADB, it only has one usb request for each direction, and maximum payload data is only 4KB, so the speed is 4MB/s at most, it needs controller to trigger interrupt as fast as possible to increase the speed. The USB performance will be better if the interrupt can be triggered faster. Reduce ITC value is benefit for USB performance, but the interrupt number is increased at the same time, it may increase cpu utilization too. Most of use case cares about performance, but some may care about cpu utilization, so, we leave a platform interface for user. We set ITC as 1 (1 micro-frame) as default value which is aligned with ehci core default value. Signed-off-by: Peter Chen <peter.chen@freescale.com> |
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| .. | ||
| bits.h | ||
| ci.h | ||
| ci_hdrc_imx.c | ||
| ci_hdrc_imx.h | ||
| ci_hdrc_msm.c | ||
| ci_hdrc_pci.c | ||
| ci_hdrc_usb2.c | ||
| ci_hdrc_zevio.c | ||
| core.c | ||
| debug.c | ||
| debug.h | ||
| host.c | ||
| host.h | ||
| Kconfig | ||
| Makefile | ||
| otg.c | ||
| otg.h | ||
| otg_fsm.c | ||
| otg_fsm.h | ||
| udc.c | ||
| udc.h | ||
| usbmisc_imx.c | ||