diff options
author | Al Cooper <alcooperx@gmail.com> | 2020-01-03 13:17:59 -0500 |
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committer | Kishon Vijay Abraham I <kishon@ti.com> | 2020-01-08 12:58:06 +0530 |
commit | dc9aa43c43668481089c48135707ec3f8f5b2e19 (patch) | |
tree | 99f9d24d585487209ccf87856a9fb879c8a386d7 /drivers/iio/imu/fxos8700_spi.c | |
parent | d0312fdbf3e1dc34bc370b17fee290921cf9b814 (diff) |
phy: usb: EHCI DMA may lose a burst of DMA data for 7255xA0 family
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>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Diffstat (limited to 'drivers/iio/imu/fxos8700_spi.c')
0 files changed, 0 insertions, 0 deletions