Re: [PATCH] ARM: dts: dra7: Disable USB metastability workaround for USB2

From: Felipe Balbi
Date: Mon Dec 04 2017 - 06:40:53 EST


Roger Quadros <rogerq@xxxxxx> writes:

> The metastability workaround causes Erratic errors [1]
> on the HighSpeed USB PHY which can cause upto 2 seconds
> delay in enumerating to a USB host while in Gadget mode.
>
> Disable the Run/Stop metastability workaround to avoid this
> ill effect. We are aware that this opens up the opportunity
> for Run/Stop metastability, however this issue has never been
> observed in TI releases so we think that Run/Stop metastability
> is a lesser evil than the PHY Erratic errors. So disable it.
>
> [1] USB controller trace during gadget enumeration
> 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@xxxxxx>

FWIW:

Acked-by: Felipe Balbi <felipe.balbi@linux/intel.com>

I'm taking the dwc3 counterpart to v4.16

--
balbi

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