Messages in this thread | | | Date | Wed, 23 Mar 2022 10:40:11 +0000 | Subject | Re: [V3] PCI: fu740: Drop to 2.5GT/s to fix initial device probing on some boards | From | Ben Dooks <> |
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On 23/03/2022 10:36, Alexandre Ghiti wrote: > On 3/21/22 14:49, Alexandre Ghiti wrote: >> Hi Ben, >> >> On 3/18/22 16:24, Ben Dooks wrote: >>> The fu740 PCIe core does not probe any devices on the SiFive Unmatched >>> board without this fix (or having U-Boot explicitly start the PCIe via >>> either boot-script or user command). The fix is to start the link at >>> 2.5GT/s speeds and once the link is up then change the maximum speed >>> back >>> to the default. >>> >>> The U-Boot driver claims to set the link-speed to 2.5GT/s to get the >>> probe >>> to work (and U-Boot does print link up at 2.5GT/s) in the following >>> code: >>> https://source.denx.de/u-boot/u-boot/-/blob/master/drivers/pci/pcie_dw_sifive.c?id=v2022.01#L271 >>> >>> >>> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
[snip]
>>> static int fu740_pcie_host_init(struct pcie_port *pp) >> >> +cc Maciej and David as there is this other fix that seems to do the >> same but differently, it's been under review for some time now: >> https://lore.kernel.org/all/20220302000043.GA662523@bhelgaas/t/ >>
I did have a quick look, but I think because we don't get any PCIe probing at-all we don't even have a device to attach to.
>> I fell onto this issue recently, I'll give your patch and the above a >> try soon. > > > FWIW, I have tested this and it solved my issue with nvme not being > probed, so: > > Tested-by: Alexandre Ghiti <alexandre.ghiti@canonical.com>
Ok, great. Our test rig seems to be still working with this.
-- Ben Dooks http://www.codethink.co.uk/ Senior Engineer Codethink - Providing Genius
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