4.19-stable review patch. If anyone has any objections, please let me know.
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From: qizhong cheng qizhong.cheng@mediatek.com
[ Upstream commit 4e11c29873a8a296a20f99b3e03095e65ebf897d ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/controller/pcie-mediatek.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c index 066e9e00de11..0d5be37660aa 100644 --- a/drivers/pci/controller/pcie-mediatek.c +++ b/drivers/pci/controller/pcie-mediatek.c @@ -605,14 +605,20 @@ 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) { virq = irq_find_mapping(port->inner_domain, bit); generic_handle_irq(virq); } } - /* Clear MSI interrupt status */ - writel(MSI_STATUS, port->base + PCIE_INT_STATUS); } }