AMD Has A One-Liner To Assist Velocity Up Linux System Resume Time
AMD engineers have been figuring out many quirks and oddities in system droop/resume dealing with to make it extra dependable on their {hardware} notably round Ryzen laptops. Along with droop/resume reliability enhancements and suspend-to-idle (s2idle) enhancements, one in every of their engineers additionally found a straightforward one-liner as a small step to rushing up system resume time.
AMD engineer Basavaraj Natikar realized a lacking examine within the USB XHCI driver can keep away from an additional 120ms delay throughout system resume time. It is solely 120 ms, however it’s a broad win given it is for the XHCI driver code and a part of their bigger effort of bettering the AMD Ryzen platform on Linux and this 120ms financial savings is from altering one line of code.
Basavaraj Natikar defined with the patch now queued in USB-next forward of the Linux 6.5 kernel cycle:
“Keep away from further 120ms delay throughout system resume.
The xHC controller could sign get up to 120ms earlier than displaying which usb machine brought on the wake on the xHC port registers.
The xhci driver due to this fact checks for port exercise as much as 120ms throughout resume, ensuring that the hub driver can see the port change, and will not instantly runtime droop again resulting from no port exercise.
That is nevertheless solely wanted for runtime resume as system resume will resume all youngster hubs and different youngster usb gadgets anyway.”
Search for this 120ms system resume time financial savings with the Linux 6.5 kernel in a number of months. Because it’s marked as a “repair” for an XHCI patch made by an Intel engineer again in 2021 the place this 120ms delay was launched, it is also doable that following the Linux 6.5 merge window this patch can be back-ported to present steady Linux kernel variations.