Messages in this thread | | | Date | Thu, 14 Feb 2019 08:01:00 +0100 | From | Lukas Wunner <> | Subject | Re: [PATCH] PCI: pciehp: Do not turn off slot if presence comes up after link |
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On Wed, Feb 13, 2019 at 06:55:46PM +0000, Alex_Gagniuc@Dellteam.com wrote: > On 2/13/19 2:36 AM, Lukas Wunner wrote: > > > (*) A bit hypothetical: There is no hardware yet implementing the ECN. > > > > Hm, this contradicts Austin Bolen's e-mail of Jan 25 that "Yes, this > > platform disables in-band presence" (when asked whether your host > > controller already adheres to the ECN). > > Both statements are true. The hardware does indeed disable in-band > presence, in a rudimentary way that is not compliant with the ECN -- it > doesn't implement the bits required by the ECN.
Ugh, can a BIOS update make those machines compliant to the ECN or do we need a quirk specifically for them?
> > Polling PDS in > > pcie_wait_for_link() or disabling either PDC or DLLSC if in-band presence > > is disabled seems simpler to reason about. > > pcie_wait_for_link() is generic PCIe layer. I don't think mixing hotplug > concepts is a good layering violation.
The function used to live in pciehp_hpc.c, but commits 9f5a70f18c58 and f0157160b359 moved it to generic code to allow code sharing with the DPC driver. That's the only reason it's in generic code AFAICS.
> >> in-band PD disable (what's a good acronym for that, BTW?) > > > > I don't know, maybe inband_presence_disabled? > > PCI_EXP_SLTCAP2_IBPD ?
Yes, something like that. It should match the spec, which I have no access to.
Thanks,
Lukas
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