On Wednesday 15 September 2021 18:52:43 Pali Rohár wrote:

On Wednesday 15 September 2021 16:38:07 gregkh@linuxfoundation.org wrote:

...

The patch below does not apply to the 5.10-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.

Hello! Below is backport for 5.10 (and probably it should apply also for older versions):

Hello Greg! Have you looked at this backport for 5.10?

From 4c801c70bdcd34ca0527d54206c0358a73154801 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Pali=20Roh=C3=A1r?= pali@kernel.org Date: Thu, 22 Jul 2021 16:40:39 +0200 Subject: [PATCH] PCI: aardvark: Increase polling delay to 1.5s while waiting for PIO response MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

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

Link: https://lore.kernel.org/r/20210722144041.12661-3-pali@kernel.org Signed-off-by: Pali Rohár pali@kernel.org Signed-off-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com 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 b1b41b61e0bd..11cf6f4e9775 100644 --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -173,7 +173,7 @@ (PCIE_CONF_BUS(bus) | PCIE_CONF_DEV(PCI_SLOT(devfn)) | \ PCIE_CONF_FUNC(PCI_FUNC(devfn)) | PCIE_CONF_REG(where)) -#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

...

thanks,

greg k-h

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

From 02bcec3ea5591720114f586960490b04b093a09e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Pali=20Roh=C3=A1r?= pali@kernel.org Date: Thu, 22 Jul 2021 16:40:39 +0200 Subject: [PATCH] PCI: aardvark: Increase polling delay to 1.5s while waiting for PIO response MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

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

Link: https://lore.kernel.org/r/20210722144041.12661-3-pali@kernel.org Signed-off-by: Pali Rohár pali@kernel.org Signed-off-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Reviewed-by: Marek Behún kabel@kernel.org Cc: stable@vger.kernel.org # 7fbcb5da811b ("PCI: aardvark: Don't rely on jiffies while holding spinlock")

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c index 8bd060e084f1..5b9e4e79c3ae 100644 --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -167,7 +167,7 @@ #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