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From: "Pali Rohár" <pali@kernel.org>
To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Bjorn Helgaas <bhelgaas@google.com>
Cc: "Marek Behún" <kabel@kernel.org>,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [RESEND PATCH 3/3] PCI: aardvark: Increase polling delay to 1.5s while waiting for PIO response
Date: Thu, 24 Jun 2021 23:33:45 +0200	[thread overview]
Message-ID: <20210624213345.3617-4-pali@kernel.org> (raw)
In-Reply-To: <20210624213345.3617-1-pali@kernel.org>

Measurements in different conditions showed that aardvark hardware PIO
response can take up to 1.44s. Increase wait timeout from 1ms to 1.5s to
ensure that we do not miss responses from hardware. After 1.44s hardware
returns errors (e.g. Completer abort).

The previous two patches fixed checking for PIO status, so now we can use
it to also catch errors which are reported by hardware after 1.44s.

After applying this patch, kernel can detect and print PIO errors to dmesg:

    [    6.879999] advk-pcie d0070000.pcie: Non-posted PIO Response Status: CA, 0xe00 @ 0x100004
    [    6.896436] advk-pcie d0070000.pcie: Posted PIO Response Status: COMP_ERR, 0x804 @ 0x100004
    [    6.913049] advk-pcie d0070000.pcie: Posted PIO Response Status: COMP_ERR, 0x804 @ 0x100010
    [    6.929663] advk-pcie d0070000.pcie: Non-posted PIO Response Status: CA, 0xe00 @ 0x100010
    [    6.953558] advk-pcie d0070000.pcie: Posted PIO Response Status: COMP_ERR, 0x804 @ 0x100014
    [    6.970170] advk-pcie d0070000.pcie: Non-posted PIO Response Status: CA, 0xe00 @ 0x100014
    [    6.994328] advk-pcie d0070000.pcie: Posted PIO Response Status: COMP_ERR, 0x804 @ 0x100004

Without this patch kernel prints only a generic error to dmesg:

    [    5.246847] advk-pcie d0070000.pcie: config read/write timed out

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <kabel@kernel.org>
Cc: stable@vger.kernel.org # 7fbcb5da811b ("PCI: aardvark: Don't rely on jiffies while holding spinlock")
---
 drivers/pci/controller/pci-aardvark.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index a37ba86f1b2d..3f3c72927afb 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -166,7 +166,7 @@
 #define PCIE_CONFIG_WR_TYPE0			0xa
 #define PCIE_CONFIG_WR_TYPE1			0xb
 
-#define PIO_RETRY_CNT			500
+#define PIO_RETRY_CNT			750000 /* 1.5 s */
 #define PIO_RETRY_DELAY			2 /* 2 us*/
 
 #define LINK_WAIT_MAX_RETRIES		10
-- 
2.20.1


  parent reply	other threads:[~2021-06-24 21:34 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-24 21:33 [RESEND PATCH 0/3] PCI: aardvark: PIO fixes Pali Rohár
2021-06-24 21:33 ` [RESEND PATCH 1/3] PCI: aardvark: Fix checking for PIO Non-posted Request Pali Rohár
2021-06-24 21:33 ` [RESEND PATCH 2/3] PCI: aardvark: Fix checking for PIO status Pali Rohár
2021-06-25 11:04   ` Lorenzo Pieralisi
2021-06-25 11:21     ` Pali Rohár
2021-07-19 23:12     ` Bjorn Helgaas
2021-07-20 14:49       ` Pali Rohár
2021-07-20 16:34         ` Bjorn Helgaas
2021-07-20 18:11           ` Pali Rohár
2021-07-20 18:30             ` Bjorn Helgaas
2021-07-21 21:05             ` Bjorn Helgaas
2021-06-24 21:33 ` Pali Rohár [this message]
2021-06-25 11:44 ` [RESEND PATCH 0/3] PCI: aardvark: PIO fixes Lorenzo Pieralisi
2021-07-22 14:40 ` [PATCH v2 0/4] " Pali Rohár
2021-07-22 14:40   ` [PATCH v2 1/4] PCI: aardvark: Fix checking for PIO status Pali Rohár
2021-07-22 14:40   ` [PATCH v2 2/4] PCI: aardvark: Increase polling delay to 1.5s while waiting for PIO response Pali Rohár
2021-07-22 14:40   ` [PATCH v2 3/4] PCI: pci-bridge-emul: Add PCIe Root Capabilities Register Pali Rohár
2021-07-22 14:40   ` [PATCH v2 4/4] PCI: aardvark: Fix reporting CRS value Pali Rohár
2021-08-05  9:54   ` [PATCH v2 0/4] PCI: aardvark: PIO fixes Lorenzo Pieralisi

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