PCI: aardvark: Increase polling delay to 1.5s while waiting for PIO response
authorPali Rohár <pali@kernel.org>
Thu, 22 Jul 2021 14:40:39 +0000 (16:40 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 22 Sep 2021 09:45:25 +0000 (11:45 +0200)
commit5c6959aebe04fe2fd557b41b1bffb2a4f8d5938e
tree3fbe8a05a0ca1c99705612237f243b6935829c2d
parent733fac7cb939d479947d8f8c0792caecc73c90cc
PCI: aardvark: Increase polling delay to 1.5s while waiting for PIO response

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 <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")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/pci/host/pci-aardvark.c