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Subject: Re: [PATCH] usb: dwc2: Skip clock gating on Samsung SoCs
To:     Marek Szyprowski <m.szyprowski@samsung.com>,
        linux-usb@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     Minas Harutyunyan <hminas@synopsys.com>,
        Felipe Balbi <felipe.balbi@linux.intel.com>,
        Artur Petrosyan <Arthur.Petrosyan@synopsys.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
References: <CGME20210716050132eucas1p285949f9a73764b173c29ad0fa8502f23@eucas1p2.samsung.com>
 <20210716050127.4406-1-m.szyprowski@samsung.com>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Message-ID: <e2fc4d3f-2f64-1d7e-5816-0275da23d6fa@canonical.com>
Date:   Fri, 16 Jul 2021 10:10:26 +0200
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On 16/07/2021 07:01, Marek Szyprowski wrote:
> Commit 0112b7ce68ea ("usb: dwc2: Update dwc2_handle_usb_suspend_intr
> function.") changed the way the driver handles power down modes in a such
> way that it uses clock gating when no other power down mode is available.
> 
> This however doesn't work well on the DWC2 implementation used on the
> Samsung SoCs. When a clock gating is enabled, system hangs. It looks that
> the proper clock gating requires some additional glue code in the shared
> USB2 PHY and/or Samsung glue code for the DWC2. To restore driver
> operation on the Samsung SoCs simply skip enabling clock gating mode
> until one finds what is really needed to make it working reliably.
> 
> Fixes: 0112b7ce68ea ("usb: dwc2: Update dwc2_handle_usb_suspend_intr function.")
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
>  drivers/usb/dwc2/core.h      | 4 ++++
>  drivers/usb/dwc2/core_intr.c | 3 ++-
>  drivers/usb/dwc2/hcd.c       | 6 ++++--
>  drivers/usb/dwc2/params.c    | 1 +
>  4 files changed, 11 insertions(+), 3 deletions(-)
> 


Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>


Best regards,
Krzysztof