From 44492e70adc8086c42d3745d21d591657a427f04 Mon Sep 17 00:00:00 2001
From: Kai-Heng Feng <kai.heng.feng@canonical.com>
Date: Tue, 29 Sep 2020 00:55:08 +0800
Subject: [PATCH] rtw88: pci: Power cycle device during shutdown
Git-commit: 44492e70adc8086c42d3745d21d591657a427f04
Patch-mainline: v5.10-rc1
References: git-fixes

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
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 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 e72ea99d9430..676d861aaf99 100644
--- a/drivers/net/wireless/realtek/rtw88/pci.c
+++ b/drivers/net/wireless/realtek/rtw88/pci.c
@@ -1601,6 +1601,8 @@ 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);
 
-- 
2.16.4