linux-kernel - Re: [PATCH v4 06/11] PCI/ASPM: Clear aspm_disable as part of __pci_enable_link

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Message-ID: <qo6mb3qlt3xpuvhepwcv6be4wd53neee2t6buzk4tdiy22xsub@vu7lykp3rnu2>
Date: Tue, 8 Jul 2025 22:45:26 +0530
From: Manivannan Sadhasivam <mani@...nel.org>
To: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>, 
	Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>, Jingoo Han <jingoohan1@...il.com>, 
	Lorenzo Pieralisi <lpieralisi@...nel.org>, Rob Herring <robh@...nel.org>, 
	Jeff Johnson <jjohnson@...nel.org>, Bartosz Golaszewski <brgl@...ev.pl>, 
	Krzysztof Wilczyński <kwilczynski@...nel.org>, linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-arm-msm@...r.kernel.org, mhi@...ts.linux.dev, linux-wireless@...r.kernel.org, 
	ath11k@...ts.infradead.org, qiang.yu@....qualcomm.com, quic_vbadigan@...cinc.com, 
	quic_vpernami@...cinc.com, quic_mrana@...cinc.com, 
	Jeff Johnson <jeff.johnson@....qualcomm.com>
Subject: Re: [PATCH v4 06/11] PCI/ASPM: Clear aspm_disable as part of
 __pci_enable_link_state()

On Mon, Jun 09, 2025 at 04:21:27PM GMT, Krishna Chaitanya Chundru wrote:
> ASPM states are not being enabled back with pci_enable_link_state() when
> they are disabled by pci_disable_link_state(). This is because of the
> aspm_disable flag is not getting cleared in pci_enable_link_state(), this
> flag is being properly cleared when ASPM is controlled by sysfs.
> 

A comment in pcie_config_aspm_link() says:

 /* Enable only the states that were not explicitly disabled */

But the function is called from both aspm_attr_store_common() and
__pci_enable_link_state(). So I don't know if this is behavior is intentional
or wrong. 

> Clear the aspm_disable flag with the requested ASPM states requested by
> pci_enable_link_state().
> 
> Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>

Fixes tag?

- Mani

> ---
>  drivers/pci/pcie/aspm.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
> index 94324fc0d3e650cd3ca2c0bb8c1895ca7e647b9d..0f858ef86111b43328bc7db01e6493ce67178458 100644
> --- a/drivers/pci/pcie/aspm.c
> +++ b/drivers/pci/pcie/aspm.c
> @@ -1453,6 +1453,7 @@ static int __pci_enable_link_state(struct pci_dev *pdev, int state, bool locked)
>  		down_read(&pci_bus_sem);
>  	mutex_lock(&aspm_lock);
>  	link->aspm_default = pci_calc_aspm_enable_mask(state);
> +	link->aspm_disable &= ~state;
>  	pcie_config_aspm_link(link, policy_to_aspm_state(link));
>  
>  	link->clkpm_default = (state & PCIE_LINK_STATE_CLKPM) ? 1 : 0;
> 
> -- 
> 2.34.1
> 

-- 
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