From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: mingchuang.qiao@mediatek.com
Cc: bhelgaas@google.com, matthias.bgg@gmail.com,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org, haijun.liu@mediatek.com,
lambert.wang@mediatek.com, kerun.zhu@mediatek.com,
alex.williamson@redhat.com, rjw@rjwysocki.net,
utkarsh.h.patel@intel.com
Subject: Re: [v4] PCI: Avoid unsync of LTR mechanism configuration
Date: Thu, 4 Feb 2021 12:00:21 +0200 [thread overview]
Message-ID: <20210204100021.GA2542@lahna.fi.intel.com> (raw)
In-Reply-To: <20210204095125.9212-1-mingchuang.qiao@mediatek.com>
On Thu, Feb 04, 2021 at 05:51:25PM +0800, mingchuang.qiao@mediatek.com wrote:
> From: Mingchuang Qiao <mingchuang.qiao@mediatek.com>
>
> In bus scan flow, the "LTR Mechanism Enable" bit of DEVCTL2 register is
> configured in pci_configure_ltr(). If device and bridge both support LTR
> mechanism, the "LTR Mechanism Enable" bit of device and bridge will be
> enabled in DEVCTL2 register. And pci_dev->ltr_path will be set as 1.
>
> If PCIe link goes down when device resets, the "LTR Mechanism Enable" bit
> of bridge will change to 0 according to PCIe r5.0, sec 7.5.3.16. However,
> the pci_dev->ltr_path value of bridge is still 1.
>
> For following conditions, check and re-configure "LTR Mechanism Enable" bit
> of bridge to make "LTR Mechanism Enable" bit match ltr_path value.
> -before configuring device's LTR for hot-remove/hot-add
> -before restoring device's DEVCTL2 register when restore device state
>
> Signed-off-by: Mingchuang Qiao <mingchuang.qiao@mediatek.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
next prev parent reply other threads:[~2021-02-04 10:03 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-04 9:51 [v4] PCI: Avoid unsync of LTR mechanism configuration mingchuang.qiao
2021-02-04 10:00 ` Mika Westerberg [this message]
2021-02-18 16:50 ` Bjorn Helgaas
2021-03-22 0:41 ` Mingchuang Qiao
2021-09-06 5:36 ` mingchuang qiao
2021-09-30 7:02 ` mingchuang qiao
2021-09-30 19:48 ` Bjorn Helgaas
2021-10-08 6:30 ` mingchuang qiao
2021-10-12 2:48 ` Rajat Jain
2021-10-12 8:01 ` Mingchuang Qiao
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