The patch below does not apply to the 4.19-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-4.19.y git checkout FETCH_HEAD git cherry-pick -x 4e11c29873a8a296a20f99b3e03095e65ebf897d # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024012227-outdoors-swivel-68c9@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..
Possible dependencies:
4e11c29873a8 ("PCI: mediatek: Clear interrupt status before dispatching handler")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 4e11c29873a8a296a20f99b3e03095e65ebf897d Mon Sep 17 00:00:00 2001 From: qizhong cheng qizhong.cheng@mediatek.com Date: Mon, 11 Dec 2023 17:49:23 +0800 Subject: [PATCH] PCI: mediatek: Clear interrupt status before dispatching handler MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
We found a failure when using the iperf tool during WiFi performance testing, where some MSIs were received while clearing the interrupt status, and these MSIs cannot be serviced.
The interrupt status can be cleared even if the MSI status remains pending. As such, given the edge-triggered interrupt type, its status should be cleared before being dispatched to the handler of the underling device.
[kwilczynski: commit log, code comment wording] Link: https://lore.kernel.org/linux-pci/20231211094923.31967-1-jianjun.wang@mediat... Fixes: 43e6409db64d ("PCI: mediatek: Add MSI support for MT2712 and MT7622") Signed-off-by: qizhong cheng qizhong.cheng@mediatek.com Signed-off-by: Jianjun Wang jianjun.wang@mediatek.com Signed-off-by: Krzysztof Wilczyński kwilczynski@kernel.org [bhelgaas: rewrap comment] Signed-off-by: Bjorn Helgaas bhelgaas@google.com Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@collabora.com Cc: stable@vger.kernel.org
diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c index 66a8f73296fc..48372013f26d 100644 --- a/drivers/pci/controller/pcie-mediatek.c +++ b/drivers/pci/controller/pcie-mediatek.c @@ -617,12 +617,18 @@ static void mtk_pcie_intr_handler(struct irq_desc *desc) if (status & MSI_STATUS){ unsigned long imsi_status;
+ /* + * The interrupt status can be cleared even if the + * MSI status remains pending. As such, given the + * edge-triggered interrupt type, its status should + * be cleared before being dispatched to the + * handler of the underlying device. + */ + writel(MSI_STATUS, port->base + PCIE_INT_STATUS); while ((imsi_status = readl(port->base + PCIE_IMSI_STATUS))) { for_each_set_bit(bit, &imsi_status, MTK_MSI_IRQS_NUM) generic_handle_domain_irq(port->inner_domain, bit); } - /* Clear MSI interrupt status */ - writel(MSI_STATUS, port->base + PCIE_INT_STATUS); } }