Re: [PATCH] PCI: brcmstb: Assign pcie->gen from pcie_get_link_speed()

Florian Fainelli
2026-05-04T16:58:29Z

On 5/2/26 04:40, Bjorn Helgaas wrote:
> On Fri, May 01, 2026 at 01:24:38PM -0700, Florian Fainelli wrote:
>> After commit 03f920936977 ("PCI: controller: Validate max-link-speed"),
>> pcie->gen stopped being assigned and as a result the established PCIe
>> link would stop supporting Gen3 speeds on 2712 since pcie->gen is used
>> to populate LnkCntl2 and LnkCap in brcm_pcie_set_gen().
>>
>> Link: https://github.com/raspberrypi/linux/issues/7343
>> Reported-by: Dom Cobley <popcornmix@gmail.com>
>> Reported-by: Phil Elwell <phil@raspberrypi.com>
>> Fixes: 03f920936977 ("PCI: controller: Validate max-link-speed")
>> Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
>> ---
>> drivers/pci/controller/pcie-brcmstb.c | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
>> index 714bcab97b60..6138fc4bc064 100644
>> --- a/drivers/pci/controller/pcie-brcmstb.c
>> +++ b/drivers/pci/controller/pcie-brcmstb.c
>> @@ -2072,8 +2072,7 @@ static int brcm_pcie_probe(struct platform_device *pdev)
>> return PTR_ERR(pcie->clk);
>>
>> ret = of_pci_get_max_link_speed(np);
>> - if (pcie_get_link_speed(ret) == PCI_SPEED_UNKNOWN)
>> - pcie->gen = 0;
>> + pcie->gen = pcie_get_link_speed(ret);
>
> Take a look at https://sashiko.dev/#/patchset/20260501202438.376033-1-florian.fainelli%40broadcom.com
>
> The notes at https://github.com/raspberrypi/linux/issues/7343 assumed
> PCI_SPEED_UNKNOWN was 0, but in fact it is 0xff, which means you might
> want the more defensive patch instead.
>
> I'll be happy to replace what's on pci/for-linus if so.

I am starting to think a revert is the simplest path forward, it's not
clear what pcie_get_link_speed() brings to the table honestly.
--
Florian