[PATCH v10 01/10] PCI: qcom: Revert "PCI: qcom: Add support for handling MSIs from 8 endpoints"

From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
To: Andy Gross <agross@kernel.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzk@kernel.org>,
	Jingoo Han <jingoohan1@gmail.com>,
	Gustavo Pimentel <gustavo.pimentel@synopsys.com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Stanimir Varbanov <svarbanov@mm-sol.com>,
	Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
	Johan Hovold <johan@kernel.org>
Cc: Vinod Koul <vkoul@kernel.org>,
	linux-arm-msm@vger.kernel.org, linux-pci@vger.kernel.org,
	devicetree@vger.kernel.org, Rob Herring <robh@kernel.org>
Subject: [PATCH v10 01/10] PCI: qcom: Revert "PCI: qcom: Add support for handling MSIs from 8 endpoints"
Date: Fri, 13 May 2022 20:26:13 +0300	[thread overview]
Message-ID: <20220513172622.2968887-2-dmitry.baryshkov@linaro.org> (raw)
In-Reply-To: <20220513172622.2968887-1-dmitry.baryshkov@linaro.org>

I have replied with my Tested-by to the patch at [2], which has landed
in the linux-next as the commit 20f1bfb8dd62 ("PCI: qcom:
Add support for handling MSIs from 8 endpoints"). However lately I
noticed that during the tests I still had 'pcie_pme=nomsi', so the
device was not forced to use higher MSI vectors.

After removing this option I noticed that high MSI vectors are not
delivered on tested platforms. Additional research pointed to
a patch in msm-4.14 ([1]), which describes that each group of MSI
vectors is mapped to the separate interrupt.

Without these changes specifying num_vectors can lead to missing MSI
interrupts and thus to devices malfunction.

[1] https://git.codelinaro.org/clo/la/kernel/msm-4.14/-/commit/671a3d5f129f4bfe477152292ada2194c8440d22
[2] https://lore.kernel.org/linux-arm-msm/20211214101319.25258-1-manivannan.sadhasivam@linaro.org/

Fixes: 20f1bfb8dd62 ("PCI: qcom: Add support for handling MSIs from 8 endpoints")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
---
 drivers/pci/controller/dwc/pcie-qcom.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index f9a61ad6d1f0..2e5464edc36e 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -1587,7 +1587,6 @@ static int qcom_pcie_probe(struct platform_device *pdev)
 	pci->dev = dev;
 	pci->ops = &dw_pcie_ops;
 	pp = &pci->pp;
-	pp->num_vectors = MAX_MSI_IRQS;
 
 	pcie->pci = pci;
 
-- 
2.35.1

