Messages in this thread | | | Subject | Re: [PATCH v4 01/13] phy: usb: EHCI DMA may lose a burst of DMA data for 7255xA0 family | From | Florian Fainelli <> | Date | Fri, 3 Jan 2020 10:22:54 -0800 |
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On 1/3/20 10:17 AM, Al Cooper wrote: > When the EHCI controller received a 512 byte USB packet that > had to be broken into 2 256 byte bursts across the SCB bus AND > there was a following 512 byte USB packet, the second burst of > data from the first packet was sometimes being lost. If the > burst size was changed to 128 bytes via the EBR_SCB_SIZE field > in the USB_CTRL_EBRIDGE register we'd see the 4th 128 byte burst > of the first packet being lost. This problem became much worse > if other threads were running that accessed memory, like a memcpy > test. Setting the EBR_SCB_SIZE to 512, which prevents breaking > the EHCI USB packet (max size of 512 bytes) into bursts, fixed > the problem. > > Signed-off-by: Al Cooper <alcooperx@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> -- Florian
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