Hi Bjorn, On Wed, Mar 22, 2023 at 05:16:24PM -0500, Bjorn Helgaas wrote: > On Tue, Mar 21, 2023 at 11:50:31AM +0200, Mika Westerberg wrote: > > The PCIe spec prescribes that a device may take up to 1 second to > > recover from reset and this same delay is prescribed when coming out of > > D3cold (as that involves reset too). The device may extend this 1 second > > delay through Request Retry Status completions and we accommondate for > > that in Linux with 60 second cap, only in reset code path, not in resume > > code path. > > > > However, a device has surfaced, namely Intel Titan Ridge xHCI, which > > requires longer delay also in the resume code path. For this reason make > > the resume code path to use this same extended delay than with the reset > > path but only after the link has come up (active link reporting is > > supported) so that we do not wait longer time for devices that have > > become permanently innaccessible during system sleep, e.g because they > > have been removed. > > > > While there move the two constants from the pci.h header into pci.c as > > these are not used outside of that file anymore. > > > > Reported-by: Chris Chiu <chris.chiu@xxxxxxxxxxxxx> > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=216728 > > Cc: Lukas Wunner <lukas@xxxxxxxxx> > > Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> > > Lukas just added the "timeout" parameter with ac91e6980563 ("PCI: > Unify delay handling for reset and resume"), so I'm going to look for > his ack for this. Of course :) > After ac91e6980563, we called pci_bridge_wait_for_secondary_bus() with > timeouts of either: > > 60s for reset (pci_bridge_secondary_bus_reset() or > dpc_reset_link()), or > > 1s for resume (pci_pm_resume_noirq() or pci_pm_runtime_resume() via > pci_pm_bridge_power_up_actions()) > > If I'm reading this right, the main changes of this patch are: > > - For slow links (<= 5 GT/s), we sleep 100ms, then previously waited > up to 1s (resume) or 60s (reset) for the device to be ready. Now > we will wait a max of 1s for both resume and reset. > > - For fast links (> 5 GT/s) we wait up to 100ms for the link to come > up and fail if it does not. If the link did come up in 100ms, we > previously waited up to 1s (resume) or 60s (reset). Now we will > wait up to 60s for both resume and reset. > > So this *reduces* the time we wait for slow links after reset, and > *increases* the time for fast links after resume. Right? Yes, this is correct.
