From: "Patel, Mayurkumar" <mayurkumar.patel@intel.com>
To: Sinan Kaya <okaya@codeaurora.org>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"timur@codeaurora.org" <timur@codeaurora.org>,
"cov@codeaurora.org" <cov@codeaurora.org>
Cc: "linux-arm-msm@vger.kernel.org" <linux-arm-msm@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
open list <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH V2] PCI/ASPM: reconfigure ASPM following hotplug for POLICY_DEFAULT
Date: Tue, 28 Feb 2017 11:03:08 +0000 [thread overview]
Message-ID: <92EBB4272BF81E4089A7126EC1E7B2846666830C@IRSMSX101.ger.corp.intel.com> (raw)
In-Reply-To: <1485891928-14573-1-git-send-email-okaya@codeaurora.org>
>
>When the operating system is booted with the default ASPM policy
>(POLICY_DEFAULT), the current code is determining the ASPM policy
>set up by the BIOS by querying the enable/disable states from ASPM
>registers.
>
>In the case of hotplug removal, the ASPM registers get cleared by
>calling the pcie_aspm_exit_link_state() function.
>
I see the same problem. So cherry-picked your change to resolve the problem
on top of Linus mainline.
>An insertion following hotplug removal reads incorrect policy as
>ASPM disabled even though ASPM was enabled during boot.
>
>Adding a flag to the struct pci_dev and saving the power up policy
>in the bridge to be reused during hotplug insertion. Bridge's enable
>counter is used as a switch to determine when to use saved value.
>
>Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
>---
> drivers/pci/pcie/aspm.c | 21 +++++++++++++++++----
> include/linux/pci.h | 1 +
> 2 files changed, 18 insertions(+), 4 deletions(-)
>
>diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
>index 17ac1dc..5cfcc6d 100644
>--- a/drivers/pci/pcie/aspm.c
>+++ b/drivers/pci/pcie/aspm.c
>@@ -338,8 +338,9 @@ static void pcie_aspm_check_latency(struct pci_dev *endpoint)
> }
> }
>
>-static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
>+static void pcie_aspm_cap_init(struct pci_dev *pdev, int blacklist)
> {
>+ struct pcie_link_state *link = pdev->link_state;
> struct pci_dev *child, *parent = link->pdev;
> struct pci_bus *linkbus = parent->subordinate;
> struct aspm_register_info upreg, dwreg;
>@@ -397,8 +398,20 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
> link->latency_up.l1 = calc_l1_latency(upreg.latency_encoding_l1);
> link->latency_dw.l1 = calc_l1_latency(dwreg.latency_encoding_l1);
>
>- /* Save default state */
>- link->aspm_default = link->aspm_enabled;
But, I am finding a problem with this change, if Policy is set to default,
BIOS enables ASPM L1, but pcie_config_aspm_link() disables ASPM L1
due to link->aspm_enabled is different than link->aspm_default while
called from pcie_aspm_init_link_state() during hotplug insertion.
>+ /*
>+ * Save default state from FW when enabling ASPM for the first time
>+ * during boot by looking at the calculated link->aspm_enabled bits
>+ * above and enable_cnt will be zero.
>+ *
>+ * If this path is getting called for the second/third time
>+ * (enable_cnt will be non-zero). Assume that the current state of the
>+ * ASPM registers may not necessarily match what FW asked us to do as
>+ * in the case of hotplug insertion/removal.
>+ */
>+ if (!atomic_read(&pdev->enable_cnt))
>+ pdev->aspm_default = link->aspm_default = link->aspm_enabled;
>+ else
>+ link->aspm_default = pdev->aspm_default;
>
> /* Setup initial capable state. Will be updated later */
> link->aspm_capable = link->aspm_support;
>@@ -599,7 +612,7 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev)
> * upstream links also because capable state of them can be
> * update through pcie_aspm_cap_init().
> */
>- pcie_aspm_cap_init(link, blacklist);
>+ pcie_aspm_cap_init(pdev, blacklist);
>
> /* Setup initial Clock PM state */
> pcie_clkpm_cap_init(link, blacklist);
>diff --git a/include/linux/pci.h b/include/linux/pci.h
>index e2d1a12..521f88c 100644
>--- a/include/linux/pci.h
>+++ b/include/linux/pci.h
>@@ -321,6 +321,7 @@ struct pci_dev {
>
> #ifdef CONFIG_PCIEASPM
> struct pcie_link_state *link_state; /* ASPM link state */
>+ unsigned int aspm_default; /* ASPM policy set by BIOS */
> #endif
>
> pci_channel_state_t error_state; /* current connectivity state */
>--
>1.9.1
>
>--
>To unsubscribe from this list: send the line "unsubscribe linux-pci" in
>the body of a message to majordomo@vger.kernel.org
>More majordomo info at http://vger.kernel.org/majordomo-info.html
Intel Deutschland GmbH
Registered Address: Am Campeon 10-12, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de
Managing Directors: Christin Eisenschmid, Christian Lamprechter
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
next prev parent reply other threads:[~2017-02-28 11:06 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-31 19:45 [PATCH V2] PCI/ASPM: reconfigure ASPM following hotplug for POLICY_DEFAULT Sinan Kaya
2017-02-28 11:03 ` Patel, Mayurkumar [this message]
2017-02-28 15:04 ` Sinan Kaya
2017-02-28 18:57 ` Patel, Mayurkumar
2017-03-01 17:58 ` Sinan Kaya
2017-03-02 16:05 ` Patel, Mayurkumar
2017-03-02 18:10 ` Sinan Kaya
2017-03-03 9:43 ` Patel, Mayurkumar
2017-03-03 10:33 ` okaya
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=92EBB4272BF81E4089A7126EC1E7B2846666830C@IRSMSX101.ger.corp.intel.com \
--to=mayurkumar.patel@intel.com \
--cc=cov@codeaurora.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=okaya@codeaurora.org \
--cc=timur@codeaurora.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).