[PATCH] PCI/ASPM: Suppress common clock mode setting failure

[PATCH] PCI/ASPM: Suppress common clock mode setting failure

[Sinan Kaya]

Code is emitting warnings when it tries to set the common clock mode for
ASPM and ASPM is already configured to common clock mode by the UEFI BIOS.
Let's bail out silently in such a case.

pci 0004:00:00.0: ASPM: Could not configure common clock

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/pci/pcie/aspm.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 9783e10..072178a 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -253,6 +253,11 @@ static void pcie_aspm_configure_common_clock(struct pcie_link_state *link)
 
 	/* Configure upstream component */
 	pcie_capability_read_word(parent, PCI_EXP_LNKCTL, &reg16);
+
+	/* Port might be already in common clock mode */
+	if ((same_clock) && (reg16 & PCI_EXP_LNKCTL_CCC))
+		return;
+
 	parent_reg = reg16;
 	if (same_clock)
 		reg16 |= PCI_EXP_LNKCTL_CCC;
-- 
1.9.1

Re: [PATCH] PCI/ASPM: Suppress common clock mode setting failure

[Sinan Kaya]

On 1/22/2018 12:28 PM, Sinan Kaya wrote:
> +++ b/drivers/pci/pcie/aspm.c
> @@ -253,6 +253,11 @@ static void pcie_aspm_configure_common_clock(struct pcie_link_state *link)
>  
>  	/* Configure upstream component */
>  	pcie_capability_read_word(parent, PCI_EXP_LNKCTL, &reg16);
> +
> +	/* Port might be already in common clock mode */
> +	if ((same_clock) && (reg16 & PCI_EXP_LNKCTL_CCC))
> +		return;
> +

I think the placement of this statement is too late. I'll move it a couple of lines
and post V2.

-- 
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.