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Date:   Mon, 11 Nov 2019 08:41:14 +0000
From:   Lee Jones <lee.jones@linaro.org>
To:     Tuowen Zhao <ztuowen@gmail.com>
Cc:     linux-kernel@vger.kernel.org, andriy.shevchenko@linux.intel.com,
        mika.westerberg@linux.intel.com, acelan.kao@canonical.com,
        mcgrof@kernel.org, davem@davemloft.net
Subject: Re: [PATCH v5 3/4] mfd: intel-lpss: use devm_ioremap_uc for MMIO
Message-ID: <20191111084114.GJ18902@dell>
References: <20191016210629.1005086-1-ztuowen@gmail.com>
 <20191016210629.1005086-4-ztuowen@gmail.com>
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On Wed, 16 Oct 2019, Tuowen Zhao wrote:

> Some BIOS erroneously specifies write-combining BAR for intel-lpss-pci
> in MTRR. This will cause the system to hang during boot. If possible,
> this bug could be corrected with a firmware update.
> 
> This patch use devm_ioremap_uc to overwrite/ignore the MTRR settings
> by forcing the use of strongly uncachable pages for intel-lpss.
> 
> The BIOS bug is present on Dell XPS 13 7390 2-in-1:
> 
> [    0.001734]   5 base 4000000000 mask 6000000000 write-combining
> 
> 4000000000-7fffffffff : PCI Bus 0000:00
>   4000000000-400fffffff : 0000:00:02.0 (i915)
>   4010000000-4010000fff : 0000:00:15.0 (intel-lpss-pci)
> 
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=203485
> Cc: <stable@vger.kernel.org>
> Tested-by: AceLan Kao <acelan.kao@canonical.com>
> Signed-off-by: Tuowen Zhao <ztuowen@gmail.com>
> Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Acked-for-MFD-by: Lee Jones <lee.jones@linaro.org>
> ---
>  drivers/mfd/intel-lpss.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Applied, thanks.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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