From: Matthias Kaehlcke <mka@chromium.org>
To: Will McVicker <willmcvicker@google.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
kernel-team@android.com, Sajid Dalvi <sdalvi@google.com>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] PCI/PM: Switch D3Hot delay to also use usleep_range
Date: Wed, 17 Aug 2022 17:27:00 -0700 [thread overview]
Message-ID: <Yv2HVLGdnNj/fwSG@google.com> (raw)
In-Reply-To: <20220817230821.47048-1-willmcvicker@google.com>
On Wed, Aug 17, 2022 at 11:08:21PM +0000, Will McVicker wrote:
> From: Sajid Dalvi <sdalvi@google.com>
>
> Since the PCI spec requires a 10ms D3Hot delay (defined by
> PCI_PM_D3HOT_WAIT) and a few of the PCI quirks update the D3Hot delay up
> to 120ms, let's add support for both usleep_range and msleep based on
> the delay time to improve the delay accuracy.
>
> This patch is based off of a commit from Sajid Dalvi <sdalvi@google.com>
> in the Pixel 6 kernel tree [1]. Testing on a Pixel 6, found that the
> 10ms delay for the Exynos PCIe device was on average delaying for 19ms
> when the spec requires 10ms. Switching from msleep to uslseep_range
> therefore decreases the resume time on a Pixel 6 on average by 9ms.
>
> [1] https://android.googlesource.com/kernel/gs/+/18a8cad68d8e6d50f339a716a18295e6d987cee3
>
> Signed-off-by: Sajid Dalvi <sdalvi@google.com>
> Signed-off-by: Will McVicker <willmcvicker@google.com>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
next prev parent reply other threads:[~2022-08-18 0:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-17 23:08 [PATCH v3] PCI/PM: Switch D3Hot delay to also use usleep_range Will McVicker
2022-08-18 0:27 ` Matthias Kaehlcke [this message]
2022-08-29 18:08 ` William McVicker
2022-09-02 22:13 ` Bjorn Helgaas
2022-09-07 0:07 ` William McVicker
2022-09-07 21:26 ` Bjorn Helgaas
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