[PATCH] dwc3: Fix fastboot re-run failure with flat DTS

[PATCH] dwc3: Fix fastboot re-run failure with flat DTS

[Balaji Selvanathan]

Problem: The first "run fastboot" works and enumerates on the host.
Subsequent runs fail, with no USB enumeration observed.

With flat DTS configurations, the peripheral device inherits
power-domains from its parent (glue) node, as both reference the
same DT node. During teardown after "fastboot continue",
device_remove() of peripheral device invokes dev_power_domain_off(),
which powers off the shared USB GDSC.

As a result, the next "run fastboot" fails because the power
domain is left in an uninitialized state.

Add DM_FLAG_LEAVE_PD_ON to dwc3_generic_peripheral to prevent
power domain shutdown during peripheral removal.

This aligns with hierarchical DTS behavior, where the peripheral
child does not own power-domains. Power management remains with
the glue device, which persists across probe/remove cycles,
allowing repeated fastboot runs to succeed.

Signed-off-by: Balaji Selvanathan <balaji.selvanathan@oss.qualcomm.com>
---
 drivers/usb/dwc3/dwc3-generic.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/dwc3/dwc3-generic.c b/drivers/usb/dwc3/dwc3-generic.c
index 22b9ef0b24e..788fe6fc819 100644
--- a/drivers/usb/dwc3/dwc3-generic.c
+++ b/drivers/usb/dwc3/dwc3-generic.c
@@ -220,6 +220,7 @@ U_BOOT_DRIVER(dwc3_generic_peripheral) = {
 	.remove = dwc3_generic_peripheral_remove,
 	.priv_auto	= sizeof(struct dwc3_generic_priv),
 	.plat_auto	= sizeof(struct dwc3_generic_plat),
+	.flags  = DM_FLAG_LEAVE_PD_ON,
 };
 #endif
 

---
base-commit: 987907ae4bcc5d6055bdf7d318a3edf53e14d5fa
change-id: 20260529-usb-3b6b44559cc5

Best regards,
-- 
Balaji Selvanathan <balaji.selvanathan@oss.qualcomm.com>

Re: [PATCH] dwc3: Fix fastboot re-run failure with flat DTS

[Marek Vasut]

On 5/29/26 2:22 PM, Balaji Selvanathan wrote:
> Problem: The first "run fastboot" works and enumerates on the host.
> Subsequent runs fail, with no USB enumeration observed.
> 
> With flat DTS configurations, the peripheral device inherits
> power-domains from its parent (glue) node, as both reference the
> same DT node. During teardown after "fastboot continue",
> device_remove() of peripheral device invokes dev_power_domain_off(),
> which powers off the shared USB GDSC.
> 
> As a result, the next "run fastboot" fails because the power
> domain is left in an uninitialized state.
> 
> Add DM_FLAG_LEAVE_PD_ON to dwc3_generic_peripheral to prevent
> power domain shutdown during peripheral removal.
It seems the driver does not handle its power domains correctly, 
inhibiting PD control is not a fix, sorry.

Re: [PATCH] dwc3: Fix fastboot re-run failure with flat DTS

[Mattijs Korpershoek]

Hi,

On Sat, May 30, 2026 at 12:02, Marek Vasut <marek.vasut@mailbox.org> wrote:

> On 5/29/26 2:22 PM, Balaji Selvanathan wrote:
>> Problem: The first "run fastboot" works and enumerates on the host.
>> Subsequent runs fail, with no USB enumeration observed.
>> 
>> With flat DTS configurations, the peripheral device inherits
>> power-domains from its parent (glue) node, as both reference the
>> same DT node. During teardown after "fastboot continue",
>> device_remove() of peripheral device invokes dev_power_domain_off(),
>> which powers off the shared USB GDSC.
>> 
>> As a result, the next "run fastboot" fails because the power
>> domain is left in an uninitialized state.
>> 
>> Add DM_FLAG_LEAVE_PD_ON to dwc3_generic_peripheral to prevent
>> power domain shutdown during peripheral removal.
> It seems the driver does not handle its power domains correctly, 
> inhibiting PD control is not a fix, sorry.

I agree with Marek here. Especially since this is a generic driver.

I had a somewhat similar problem on amlogic devices where I could only
run fastboot once.

I've solved this via
https://lore.kernel.org/all/20221024-meson-dm-usb-v1-1-2ab077a503b9@baylibre.com/

Maybe you can explore something similar instead?

Re: [PATCH] dwc3: Fix fastboot re-run failure with flat DTS

[Balaji Selvanathan]

Hi Mattijs,

On 6/8/2026 12:45 PM, Mattijs Korpershoek wrote:
> Hi,
>
> On Sat, May 30, 2026 at 12:02, Marek Vasut <marek.vasut@mailbox.org> wrote:
>
>> On 5/29/26 2:22 PM, Balaji Selvanathan wrote:
>>> Problem: The first "run fastboot" works and enumerates on the host.
>>> Subsequent runs fail, with no USB enumeration observed.
>>>
>>> With flat DTS configurations, the peripheral device inherits
>>> power-domains from its parent (glue) node, as both reference the
>>> same DT node. During teardown after "fastboot continue",
>>> device_remove() of peripheral device invokes dev_power_domain_off(),
>>> which powers off the shared USB GDSC.
>>>
>>> As a result, the next "run fastboot" fails because the power
>>> domain is left in an uninitialized state.
>>>
>>> Add DM_FLAG_LEAVE_PD_ON to dwc3_generic_peripheral to prevent
>>> power domain shutdown during peripheral removal.
>> It seems the driver does not handle its power domains correctly,
>> inhibiting PD control is not a fix, sorry.
> I agree with Marek here. Especially since this is a generic driver.
>
> I had a somewhat similar problem on amlogic devices where I could only
> run fastboot once.
>
> I've solved this via
> https://lore.kernel.org/all/20221024-meson-dm-usb-v1-1-2ab077a503b9@baylibre.com/
>
> Maybe you can explore something similar instead?

Thanks, will look into this patch.

Regards,

Balaji