From: Greg Kroah-Hartman Date: Fri, 12 Sep 2025 12:08:09 +0000 (+0200) Subject: Merge patch series "Support system sleep with offloaded usb transfers" into usb-next X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=44bbcba50d55ca97e09b0eaa7c1e6bf97b9f425d;p=users%2Fhch%2Fmisc.git Merge patch series "Support system sleep with offloaded usb transfers" into usb-next Guan-Yu Lin says: Wesley Cheng and Mathias Nyman's USB offload design enables a co-processor to handle some USB transfers, potentially allowing the system to sleep (suspend-to-RAM) and save power. However, Linux's System Sleep model halts the USB host controller when the main system isn't managing any USB transfers. To address this, the proposal modifies the system to recognize offloaded USB transfers and manage power accordingly. This way, offloaded USB transfers could still happen during system sleep (Suspend-to-RAM). This involves two key steps: 1. Transfer Status Tracking: Propose offload_usage and corresponding apis drivers could track USB transfers on the co-processor, ensuring the system is aware of any ongoing activity. 2. Power Management Adjustment: Modifications to the USB driver stack (xhci host controller driver, and USB device drivers) allow the system to sleep (Suspend-to-RAM) without disrupting co-processor managed USB transfers. This involves adding conditional checks to bypass some power management operations in the System Sleep model. Link: https://lore.kernel.org/r/20250911142051.90822-1-guanyulin@google.com Signed-off-by: Greg Kroah-Hartman --- 44bbcba50d55ca97e09b0eaa7c1e6bf97b9f425d