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ARM: dts: dra7: Disable USB metastability workaround for USB2

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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@ti.com>
Acked-by: Felipe Balbi <felipe.balbi@linux/intel.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
This commit is contained in:
Roger Quadros 2017-10-31 15:26:00 +02:00 committed by Tony Lindgren
parent 5f9ca11f25
commit b8c9c6fa20
1 changed files with 1 additions and 0 deletions
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arch/arm/boot/dts/dra7.dtsi
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@ -1547,6 +1547,7 @@
dr_mode = "otg";
snps,dis_u3_susphy_quirk;
snps,dis_u2_susphy_quirk;
snps,dis_metastability_quirk;
};
};