From: Dmitry Osipenko <digetx@gmail.com>
To: Thierry Reding <thierry.reding@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Alan Stern <stern@rowland.harvard.edu>,
Felipe Balbi <balbi@kernel.org>,
Maxim Schwalm <maxim.schwalm@gmail.com>,
Peter Chen <peter.chen@kernel.org>
Cc: linux-tegra@vger.kernel.org, linux-usb@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1] usb: chipidea: tegra: Delay PHY suspending
Date: Wed, 9 Jun 2021 15:07:31 +0300 [thread overview]
Message-ID: <d476a149-1b97-9762-fbc7-5ba41f72523b@gmail.com> (raw)
In-Reply-To: <20210609120404.3991-1-digetx@gmail.com>
09.06.2021 15:04, Dmitry Osipenko пишет:
> The ChipIdea driver enters into suspend immediately after seeing a
> VBUS disconnection. Some devices need an extra delay after losing
> VBUS, otherwise VBUS may be floating, preventing the PHY's suspending
> by the VBUS detection sensors. This problem was found on Tegra30 Asus
> Transformer TF700T tablet device, where the USB PHY wakes up immediately
> from suspend because VBUS sensor continues to detect VBUS as active after
> disconnection. A minimum delay of 20ms is needed in order to fix this
> issue, hence add 25ms delay before suspending the PHY.
>
> Reported-by: Maxim Schwalm <maxim.schwalm@gmail.com> # Asus TF700T
> Tested-by: Maxim Schwalm <maxim.schwalm@gmail.com> # Asus TF700T
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
> drivers/usb/chipidea/ci_hdrc_tegra.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/usb/chipidea/ci_hdrc_tegra.c b/drivers/usb/chipidea/ci_hdrc_tegra.c
> index 60361141ac04..d1359b76a0e8 100644
> --- a/drivers/usb/chipidea/ci_hdrc_tegra.c
> +++ b/drivers/usb/chipidea/ci_hdrc_tegra.c
> @@ -4,6 +4,7 @@
> */
>
> #include <linux/clk.h>
> +#include <linux/delay.h>
> #include <linux/io.h>
> #include <linux/module.h>
> #include <linux/of_device.h>
> @@ -255,6 +256,13 @@ static int tegra_ehci_hub_control(struct ci_hdrc *ci, u16 typeReq, u16 wValue,
>
> static void tegra_usb_enter_lpm(struct ci_hdrc *ci, bool enable)
> {
> + /*
> + * Give hardware time to settle down after VBUS disconnection,
> + * otherwise PHY may wake up from suspend immediately.
> + */
> + if (enable)
> + msleep(25);
> +
> /*
> * Touching any register which belongs to AHB clock domain will
> * hang CPU if USB controller is put into low power mode because
>
I missed that Peter's email address changed. Making this reply to the
new address for visibility.
next prev parent reply other threads:[~2021-06-09 12:08 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-09 12:04 [PATCH v1] usb: chipidea: tegra: Delay PHY suspending Dmitry Osipenko
2021-06-09 12:07 ` Dmitry Osipenko [this message]
2021-06-12 7:34 ` Peter Chen
2021-06-12 13:55 ` Dmitry Osipenko
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