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

Message ID 1509456360-2638-1-git-send-email-rogerq@ti.com
State New
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Series
  • ARM: dts: dra7: Disable USB metastability workaround for USB2
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Commit Message

Roger Quadros Oct. 31, 2017, 1:26 p.m.
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>

---
 arch/arm/boot/dts/dra7.dtsi | 1 +
 1 file changed, 1 insertion(+)

-- 
cheers,
-roger

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

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Comments

Felipe Balbi Dec. 4, 2017, 11:40 a.m. | #1
Roger Quadros <rogerq@ti.com> 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@ti.com>


FWIW:

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


I'm taking the dwc3 counterpart to v4.16

-- 
balbi
Tony Lindgren Dec. 11, 2017, 4:47 p.m. | #2
* Felipe Balbi <balbi@kernel.org> [171204 11:43]:
> Roger Quadros <rogerq@ti.com> 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@ti.com>

> 

> FWIW:

> 

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

> 

> I'm taking the dwc3 counterpart to v4.16


OK applying this into omap-for-v4.16/dt thanks.

Tony

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Patch

diff --git a/arch/arm/boot/dts/dra7.dtsi b/arch/arm/boot/dts/dra7.dtsi
index 02a136a..1264e39 100644
--- a/arch/arm/boot/dts/dra7.dtsi
+++ b/arch/arm/boot/dts/dra7.dtsi
@@ -1540,6 +1540,7 @@ 
 				dr_mode = "otg";
 				snps,dis_u3_susphy_quirk;
 				snps,dis_u2_susphy_quirk;
+				snps,dis_metastability_quirk;
 			};
 		};