FAILED: patch "[PATCH] wifi: rtw88: check for PCI upstream bridge existence" failed to apply to 5.15-stable tree

FAILED: patch "[PATCH] wifi: rtw88: check for PCI upstream bridge existence" failed to apply to 5.15-stable tree

[gregkh]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x eb101d2abdcccb514ca4fccd3b278dd8267374f6
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026043013-untainted-dominion-7f06@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From eb101d2abdcccb514ca4fccd3b278dd8267374f6 Mon Sep 17 00:00:00 2001
From: Fedor Pchelkin <pchelkin@ispras.ru>
Date: Fri, 20 Feb 2026 12:47:30 +0300
Subject: [PATCH] wifi: rtw88: check for PCI upstream bridge existence

pci_upstream_bridge() returns NULL if the device is on a root bus.  If
8821CE is installed in the system with such a PCI topology, the probing
routine will crash.  This has probably been unnoticed as 8821CE is mostly
supplied in laptops where there is a PCI-to-PCI bridge located upstream
from the device.  However the card might be installed on a system with
different configuration.

Check if the bridge does exist for the specific workaround to be applied.

Found by Linux Verification Center (linuxtesting.org) with Svace static
analysis tool.

Fixes: 24f5e38a13b5 ("rtw88: Disable PCIe ASPM while doing NAPI poll on 8821CE")
Cc: stable@vger.kernel.org
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20260220094730.49791-1-pchelkin@ispras.ru

diff --git a/drivers/net/wireless/realtek/rtw88/pci.c b/drivers/net/wireless/realtek/rtw88/pci.c
index 56b16186d3aa..ec0a45bfb670 100644
--- a/drivers/net/wireless/realtek/rtw88/pci.c
+++ b/drivers/net/wireless/realtek/rtw88/pci.c
@@ -1804,7 +1804,8 @@ int rtw_pci_probe(struct pci_dev *pdev,
 	}
 
 	/* Disable PCIe ASPM L1 while doing NAPI poll for 8821CE */
-	if (rtwdev->chip->id == RTW_CHIP_TYPE_8821C && bridge->vendor == PCI_VENDOR_ID_INTEL)
+	if (rtwdev->chip->id == RTW_CHIP_TYPE_8821C &&
+	    bridge && bridge->vendor == PCI_VENDOR_ID_INTEL)
 		rtwpci->rx_no_aspm = true;
 
 	rtw_pci_phy_cfg(rtwdev);

[PATCH 5.15.y 1/2] rtw88: 8821ce: Disable PCIe ASPM L1 for 8821CE using chip ID

[Sasha Levin]

From: Jimmy Hon <honyuenkwun@gmail.com>

[ Upstream commit b9eb5f0742d107ca9c0f33da58f61ce83e3ce2fc ]

Make workaround work for other 8821CE devices with different PCI ID

Signed-off-by: Jimmy Hon <honyuenkwun@gmail.com>
Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220407075123.420696-3-honyuenkwun@gmail.com
Stable-dep-of: eb101d2abdcc ("wifi: rtw88: check for PCI upstream bridge existence")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/realtek/rtw88/pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/realtek/rtw88/pci.c b/drivers/net/wireless/realtek/rtw88/pci.c
index 08cf66141889b..0d1b1dfab8a2c 100644
--- a/drivers/net/wireless/realtek/rtw88/pci.c
+++ b/drivers/net/wireless/realtek/rtw88/pci.c
@@ -1766,7 +1766,7 @@ int rtw_pci_probe(struct pci_dev *pdev,
 	}
 
 	/* Disable PCIe ASPM L1 while doing NAPI poll for 8821CE */
-	if (pdev->device == 0xc821 && bridge->vendor == PCI_VENDOR_ID_INTEL)
+	if (rtwdev->chip->id == RTW_CHIP_TYPE_8821C && bridge->vendor == PCI_VENDOR_ID_INTEL)
 		rtwpci->rx_no_aspm = true;
 
 	rtw_pci_phy_cfg(rtwdev);
-- 
2.53.0

[PATCH 5.15.y 2/2] wifi: rtw88: check for PCI upstream bridge existence

[Sasha Levin]

From: Fedor Pchelkin <pchelkin@ispras.ru>

[ Upstream commit eb101d2abdcccb514ca4fccd3b278dd8267374f6 ]

pci_upstream_bridge() returns NULL if the device is on a root bus.  If
8821CE is installed in the system with such a PCI topology, the probing
routine will crash.  This has probably been unnoticed as 8821CE is mostly
supplied in laptops where there is a PCI-to-PCI bridge located upstream
from the device.  However the card might be installed on a system with
different configuration.

Check if the bridge does exist for the specific workaround to be applied.

Found by Linux Verification Center (linuxtesting.org) with Svace static
analysis tool.

Fixes: 24f5e38a13b5 ("rtw88: Disable PCIe ASPM while doing NAPI poll on 8821CE")
Cc: stable@vger.kernel.org
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20260220094730.49791-1-pchelkin@ispras.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/realtek/rtw88/pci.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/realtek/rtw88/pci.c b/drivers/net/wireless/realtek/rtw88/pci.c
index 0d1b1dfab8a2c..fa302d5e7839d 100644
--- a/drivers/net/wireless/realtek/rtw88/pci.c
+++ b/drivers/net/wireless/realtek/rtw88/pci.c
@@ -1766,7 +1766,8 @@ int rtw_pci_probe(struct pci_dev *pdev,
 	}
 
 	/* Disable PCIe ASPM L1 while doing NAPI poll for 8821CE */
-	if (rtwdev->chip->id == RTW_CHIP_TYPE_8821C && bridge->vendor == PCI_VENDOR_ID_INTEL)
+	if (rtwdev->chip->id == RTW_CHIP_TYPE_8821C &&
+	    bridge && bridge->vendor == PCI_VENDOR_ID_INTEL)
 		rtwpci->rx_no_aspm = true;
 
 	rtw_pci_phy_cfg(rtwdev);
-- 
2.53.0