Messages in this thread | | | Date | Fri, 18 Mar 2022 15:25:10 +0000 | Subject | Re: [PATCH] PCI: fu740: Drop to 2.5GT/s to fix initial device probing on some boards | From | Ben Dooks <> |
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On 18/03/2022 15:21, 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> > -- > Note, this patch has had significant re-work since the previous 4 > sets, including trying to fix style, message, reliance on the U-Boot > fix and the comments about usage of LINK_CAP and reserved fields.
Apologies, it seems I forgot to do "git commit --amend" on the last file save. I've now sent a "V3"
-- Ben Dooks http://www.codethink.co.uk/ Senior Engineer Codethink - Providing Genius
https://www.codethink.co.uk/privacy.html
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