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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Kai-Heng Feng <kai.heng.feng@canonical.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.9 686/757] rtw88: pci: Power cycle device during shutdown
Date:   Tue, 27 Oct 2020 14:55:36 +0100
Message-Id: <20201027135522.705929633@linuxfoundation.org>
In-Reply-To: <20201027135450.497324313@linuxfoundation.org>
References: <20201027135450.497324313@linuxfoundation.org>
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From: Kai-Heng Feng <kai.heng.feng@canonical.com>

[ Upstream commit 44492e70adc8086c42d3745d21d591657a427f04 ]

There are reports that 8822CE fails to work rtw88 with "failed to read DBI
register" error. Also I have a system with 8723DE which freezes the whole
system when the rtw88 is probing the device.

According to [1], platform firmware may not properly power manage the
device during shutdown. I did some expirements and putting the device to
D3 can workaround the issue.

So let's power cycle the device by putting the device to D3 at shutdown
to prevent the issue from happening.

[1] https://bugzilla.kernel.org/show_bug.cgi?id=206411#c9

BugLink: https://bugs.launchpad.net/bugs/1872984
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200928165508.20775-1-kai.heng.feng@canonical.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/realtek/rtw88/pci.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/wireless/realtek/rtw88/pci.c b/drivers/net/wireless/realtek/rtw88/pci.c
index 3413973bc4750..7f1f5073b9f4d 100644
--- a/drivers/net/wireless/realtek/rtw88/pci.c
+++ b/drivers/net/wireless/realtek/rtw88/pci.c
@@ -1599,6 +1599,8 @@ void rtw_pci_shutdown(struct pci_dev *pdev)
 
 	if (chip->ops->shutdown)
 		chip->ops->shutdown(rtwdev);
+
+	pci_set_power_state(pdev, PCI_D3hot);
 }
 EXPORT_SYMBOL(rtw_pci_shutdown);
 
-- 
2.25.1