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| author | Roger Quadros <rogerq@ti.com> | 2017-10-31 15:11:55 +0200 |
|---|---|---|
| committer | Felipe Balbi <felipe.balbi@linux.intel.com> | 2017-12-11 12:36:53 +0200 |
| commit | 42bf02ec6e420e541af9a47437d0bdf961ca2972 (patch) | |
| tree | d26f219a5d67aad75da1ec0db2e7a71fe0164352 /Documentation/devicetree/bindings/usb | |
| parent | d855e08cf623835bc3208209cd9ab32d6c710162 (diff) | |
| download | linux-42bf02ec6e420e541af9a47437d0bdf961ca2972.tar.bz2 | |
usb: dwc3: Allow disabling of metastability workaround
Some platforms (e.g. TI's DRA7 USB2 instance) have more trouble
with the metastability workaround as it supports only
a High-Speed PHY and the PHY can enter into an Erratic state [1]
when the controller is set in SuperSpeed mode as part of
the metastability workaround.
This causes upto 2 seconds delay in enumeration on DRA7's USB2
instance in gadget mode.
If these platforms can be better off without the workaround,
provide a device tree property to suggest that so the workaround
is avoided.
[1] Device mode enumeration trace showing PHY Erratic Error.
irq/90-dwc3-969 [000] d... 52.323145: dwc3_event: event (00000901): Erratic Error [U0]
irq/90-dwc3-969 [000] d... 52.560646: dwc3_event: event (00000901): Erratic Error [U0]
irq/90-dwc3-969 [000] d... 52.798144: dwc3_event: event (00000901): Erratic Error [U0]
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Diffstat (limited to 'Documentation/devicetree/bindings/usb')
| -rw-r--r-- | Documentation/devicetree/bindings/usb/dwc3.txt | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt index 52fb41046b34..44e8bab159ad 100644 --- a/Documentation/devicetree/bindings/usb/dwc3.txt +++ b/Documentation/devicetree/bindings/usb/dwc3.txt @@ -47,6 +47,8 @@ Optional properties: from P0 to P1/P2/P3 without delay. - snps,dis-tx-ipgap-linecheck-quirk: when set, disable u2mac linestate check during HS transmit. + - snps,dis_metastability_quirk: when set, disable metastability workaround. + CAUTION: use only if you are absolutely sure of it. - snps,is-utmi-l1-suspend: true when DWC3 asserts output signal utmi_l1_suspend_n, false when asserts utmi_sleep_n - snps,hird-threshold: HIRD threshold |