All of lore.kernel.org
 help / color / mirror / Atom feed
From: Lukas Wunner <lukas@wunner.de>
To: lirongqing <lirongqing@baidu.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	Niklas Schnelle <schnelle@linux.ibm.com>,
	Farhan Ali <alifm@linux.ibm.com>,
	Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>,
	Frank Li <Frank.Li@nxp.com>,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] PCI: Only restore state that was successfully saved around a reset
Date: Tue, 10 Nov 2026 11:13:45 +0100	[thread overview]
Message-ID: <avLuWagPGyPhLYvl@wunner.de> (raw)
In-Reply-To: <20261110053348.2419-1-lirongqing@baidu.com>

On Tue, Nov 10, 2026 at 01:33:47PM +0800, lirongqing wrote:
> pci_dev_save_and_disable() returns early when config space is inaccessible,
> without saving anything, but pci_dev_restore() calls pci_restore_state()
> unconditionally and pci_restore_state() does not look at state_saved. After
> the reset makes config space accessible again, the all-zero or stale
> saved_config_space[] array is written back to the device, clearing Command,
> BARs and, for bridges, the bus number registers.
> 
> Clear state_saved when the save is skipped and only restore when a state
> was saved.

The state_saved flag is used internally by the PCI core for
suspend/resume.  If a driver calls pci_save_state() on suspend,
the flag is set and that tells the PCI core that the driver already
put the device into a lower power state, obviating the need for the
PCI core to do that.

Please do not use the flag for a completely different purpose.

Thanks,

Lukas

  parent reply	other threads:[~2026-11-10 10:13 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-11-10  5:33 [PATCH] PCI: Only restore state that was successfully saved around a reset lirongqing
2026-11-10  5:33 ` [PATCH] PCI: Save the Root Port state before a platform-specific reset lirongqing
2026-11-10  5:55   ` sashiko-bot
2026-11-10  8:19     ` 答复: [外部邮件] " Li,Rongqing
2026-11-10 10:16   ` Lukas Wunner
2026-11-12  2:47     ` 答复: [????] " Li,Rongqing
2026-11-10  5:51 ` [PATCH] PCI: Only restore state that was successfully saved around a reset sashiko-bot
2026-11-10  8:17   ` 答复: [外部邮件] " Li,Rongqing
2026-11-10 10:13 ` Lukas Wunner [this message]
2026-11-10 18:09 ` Farhan Ali
2026-11-12  2:31   ` 答复: [外部邮件] " Li,Rongqing

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=avLuWagPGyPhLYvl@wunner.de \
    --to=lukas@wunner.de \
    --cc=Frank.Li@nxp.com \
    --cc=alifm@linux.ibm.com \
    --cc=bhelgaas@google.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pci@vger.kernel.org \
    --cc=lirongqing@baidu.com \
    --cc=manivannan.sadhasivam@oss.qualcomm.com \
    --cc=schnelle@linux.ibm.com \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.