linux-kernel - Re: [PATCH] USB: core: Add warm reset while reset-resuming SuperSpeed HUBs

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Date:	Mon, 9 Dec 2013 18:21:10 +0530
From:	Vivek Gautam <gautamvivek1987@...il.com>
To:	Vikas Sajjan <vikas.sajjan@...aro.org>
Cc:	"linux-samsung-soc@...r.kernel.org" 
	<linux-samsung-soc@...r.kernel.org>,
	Kukjin Kim <kgene.kim@...sung.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Linux USB Mailing List <linux-usb@...r.kernel.org>,
	Sarah Sharp <sarah.a.sharp@...ux.intel.com>,
	Alan Stern <stern@...land.harvard.edu>, vpalatin@...omium.org,
	Julius Werner <jwerner@...omium.org>, tianyu.lan@...el.com,
	burzalodowa@...il.com, Greg KH <gregkh@...uxfoundation.org>,
	Vivek Gautam <gautam.vivek@...sung.com>,
	Doug Anderson <dianders@...omium.org>,
	Felipe Balbi <balbi@...com>, sunil joshi <joshi@...sung.com>
Subject: Re: [PATCH] USB: core: Add warm reset while reset-resuming SuperSpeed HUBs

Hi Vikas,


On Mon, Dec 9, 2013 at 5:59 PM, Vikas Sajjan <vikas.sajjan@...aro.org> wrote:

few minor nits here. ;-)

> Does warm reset while activating SuperSpeed HUBs if the hub activate type
> is HUB_RESET_RESUME.
>
> When we do Suspend-to-RAM with (any one of the 16, 32, 64 Jetflash) transcend
> USB 3.0 device connected on 3.0 port, during resume I noticed that the
> XHCI controller has moved to sometimes RECOVERY, POLLING or INACTIVE STATE.
> This behaviour is inconsistent and the connection with connected USB 3.0 device
> on 3.0 port was LOST.
>
> Doing warm reset while activating SuperSpeed HUBs if the hub
> activate type is HUB_RESET_RESUME, gets the connected device to the stable state.
>
> Reviewed at https://chromium-review.googlesource.com/#/c/177132/
>
> Tested on exynos5420 and exynos5250 with Transcend Jetflash USB 3.0 device (8564:1000)
>
> rebased on Greg Kroah-Hartman's usb-next
> git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git

Above two lines may not be required in the commit message.

>
> Signed-off-by: Vikas Sajjan <vikas.sajjan@...sung.com>
> ---
>  drivers/usb/core/hub.c |   41 +++++++++++++++++++++++++----------------
>  1 file changed, 25 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index a7c04e2..d8432b0 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -993,6 +993,21 @@ int usb_remove_device(struct usb_device *udev)
>         return 0;
>  }
>
> +#define PORT_RESET_TRIES       5
> +#define SET_ADDRESS_TRIES      2
> +#define GET_DESCRIPTOR_TRIES   2
> +#define SET_CONFIG_TRIES       (2 * (use_both_schemes + 1))
> +#define USE_NEW_SCHEME(i)      ((i) / 2 == (int)old_scheme_first)
> +
> +#define HUB_ROOT_RESET_TIME    50      /* times are in msec */
> +#define HUB_SHORT_RESET_TIME   10
> +#define HUB_BH_RESET_TIME      50
> +#define HUB_LONG_RESET_TIME    200
> +#define HUB_RESET_TIMEOUT      800
> +
> +static int hub_port_reset(struct usb_hub *hub, int port1,
> +                       struct usb_device *udev, unsigned int delay, bool warm);
> +
>  enum hub_activation_type {
>         HUB_INIT, HUB_INIT2, HUB_INIT3,         /* INITs must come first */
>         HUB_POST_RESET, HUB_RESUME, HUB_RESET_RESUME,
> @@ -1093,6 +1108,16 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
>                 u16 portstatus, portchange;
>
>                 portstatus = portchange = 0;
> +
> +               /* Some connected devices might be still in unknown state even
Please take care of multiple line commenting style.

> +                * after reset-resume, a WARM_RESET gets the connected device
> +                * to the normal state.
> +                */
> +               if (udev && hub_is_superspeed(hub->hdev) &&
> +                                               type == HUB_RESET_RESUME)
> +                       hub_port_reset(hub, port1, NULL,
> +                                               HUB_BH_RESET_TIME, true);
> +
>                 status = hub_port_status(hub, port1, &portstatus, &portchange);
>                 if (udev || (portstatus & USB_PORT_STAT_CONNECTION))
>                         dev_dbg(hub->intfdev,
> @@ -2510,22 +2535,6 @@ static unsigned hub_is_wusb(struct usb_hub *hub)
>         return hcd->wireless;
>  }
>
> -
> -#define PORT_RESET_TRIES       5
> -#define SET_ADDRESS_TRIES      2
> -#define GET_DESCRIPTOR_TRIES   2
> -#define SET_CONFIG_TRIES       (2 * (use_both_schemes + 1))
> -#define USE_NEW_SCHEME(i)      ((i) / 2 == (int)old_scheme_first)
> -
> -#define HUB_ROOT_RESET_TIME    50      /* times are in msec */
> -#define HUB_SHORT_RESET_TIME   10
> -#define HUB_BH_RESET_TIME      50
> -#define HUB_LONG_RESET_TIME    200
> -#define HUB_RESET_TIMEOUT      800
> -
> -static int hub_port_reset(struct usb_hub *hub, int port1,
> -                       struct usb_device *udev, unsigned int delay, bool warm);
> -
>  /* Is a USB 3.0 port in the Inactive or Complinance Mode state?
>   * Port worm reset is required to recover
>   */
> --
> 1.7.9.5
>
> --
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-- 
Best Regards
Vivek Gautam
Samsung R&D Institute, Bangalore
India
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