ACK: [PATCH 1/1][F/H] UBUNTU: SAUCE: Revert "usb: core: reduce power-on-good delay time of root hub"

[Stefan Bader]

On 12.08.21 15:35, Chris Chiu wrote:
> BugLink: https://bugs.launchpad.net/bugs/1939638
> 
> This reverts commit 49b64d3f82f33f9bdd313538795dc00c3f85090c.
> 
> The USB devices will fail to be detected if the power-on-good delay
> of the root hub is not long enough. In the problematic root hub,
> it claims 20 ms of bPwrOn2PwrGood in the hub descriptor, but we
> have to increase it to 100ms to make all connected USB devices to
> be correctly enumerated and detected. Revert the commit until a
> formal fix from upstream.
> 
> Signed-off-by: Chris Chiu <chris.chiu at canonical.com>
Acked-by: Stefan Bader <stefan.bader at canonical.com>
> ---
>   drivers/usb/core/hub.h | 6 ++----
>   1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h
> index 5bd2831dc992..92fc6c8f54eb 100644
> --- a/drivers/usb/core/hub.h
> +++ b/drivers/usb/core/hub.h
> @@ -147,10 +147,8 @@ static inline unsigned hub_power_on_good_delay(struct usb_hub *hub)
>   {
>   	unsigned delay = hub->descriptor->bPwrOn2PwrGood * 2;
>   
> -	if (!hub->hdev->parent)	/* root hub */
> -		return delay;
> -	else /* Wait at least 100 msec for power to become stable */
> -		return max(delay, 100U);
> +	/* Wait at least 100 msec for power to become stable */
> +	return max(delay, 100U);
>   }
>   
>   static inline int hub_port_debounce_be_connected(struct usb_hub *hub,
> 


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