From 88a2a1aab27ae76afc9fb2c60e5174a14a0c6e9e Mon Sep 17 00:00:00 2001 From: =?utf8?q?Pali=20Roh=C3=A1r?= 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=utf8 Content-Transfer-Encoding: 8bit BugLink: https://bugs.launchpad.net/bugs/1947781 commit 02bcec3ea5591720114f586960490b04b093a09e upstream. 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 Signed-off-by: Lorenzo Pieralisi Reviewed-by: Marek Behún Cc: stable@vger.kernel.org # 7fbcb5da811b ("PCI: aardvark: Don't rely on jiffies while holding spinlock") Signed-off-by: Greg Kroah-Hartman Signed-off-by: Kamal Mostafa Signed-off-by: Kelsey Skunberg --- 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 1c4ad7a47130..fdbf05158697 100644 --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -207,7 +207,7 @@ #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 -- 2.39.5