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From:   =?UTF-8?B?SsOhbiBWZXNlbMO9?= <jano.vesely@gmail.com>
Date:   Wed, 10 Jul 2019 00:38:32 -0400
Message-ID: <CA+K+NcRWLeE3-vah=urveMVxcgXYO0yFHYD=WNeuX_TdZ9+8-A@mail.gmail.com>
Subject: [5.2 regression] rtwpci + amd iommu
To:     linux-wireless <linux-wireless@vger.kernel.org>
Cc:     yhchuang@realtek.com
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Sender: linux-wireless-owner@vger.kernel.org
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Hi,

after updating to 5.2 the wi-fi driver stopped working when the iommu
is enabled.
It fails to list the available wi-fi networks or connect to a known one.
booting with amd_iommu=off works around the problem.
The staging version in 5.1 and older worked OK with the iommu enabled

The device is:
04:00.0 Network controller: Realtek Semiconductor Co., Ltd. RTL8822BE
802.11a/b/g/n/ac WiFi adapter

I do see an IOMMU error in dmesg, but the originating device does not
match the nics pci location:
Jul 08 15:03:14 host kernel: rtw_pci 0000:04:00.0: start vif
xx:xx:xx:xx:xx:xx on port 0
Jul 08 15:03:14 host kernel: iommu ivhd0: AMD-Vi: Event logged
[INVALID_DEVICE_REQUEST device=00:00.1 pasid=0x00000
address=0xfffffffdf8140200 flags=0x0a00]
Jul 08 15:03:14 host kernel: rtw_pci 0000:04:00.0: stop vif
xx:xx:xx:xx:xx:xx on port 0
Jul 08 15:03:14 host NetworkManager[790]: <info>  [1562612594.8992]
device (wlp4s0): set-hw-addr: set MAC address to yy:yy:yy:yy:yy:yy
(scanning)
Jul 08 15:03:15 host kernel: rtw_pci 0000:04:00.0: start vif
yy:yy:yy:yy:yy:yy on port 0

let me know if I should provide any further info.
thanks,
Jan