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3c3f691df9
Manually rebased: bcm27xx/patches-6.12/950-0018-arm64-setup-Fix-build-warning.patch All other patches automatically rebased. Signed-off-by: John Audia <therealgraysky@proton.me>
61 lines
2.3 KiB
Diff
61 lines
2.3 KiB
Diff
From fbadc723477d9cfe1d7c758bd1465d0e455565f0 Mon Sep 17 00:00:00 2001
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From: Jonathan Bell <jonathan@raspberrypi.com>
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Date: Tue, 15 Apr 2025 14:44:07 +0100
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Subject: [PATCH] usb: xhci: default to Intel scheme for calculating U1/U2
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timeouts
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By default, the System Exit Latency and Maximum Exit Latency are used to
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calculate hub port U1 and U2 timeout values. This has the effect of
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aggressively power-managing a SuperSpeed link but devices are known to
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report unfeasibly short device exit latencies in their descriptors,
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which under certain usage conditions can significantly degrade
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throughput as the link spends longer retraining than being in a useable
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state.
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The Intel heuristic approach calculates a reasonably large
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endpoint-dependent U1 timeout, and uses a minimum U2 timeout that is
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several multiples of typical U2 exit latencies.
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Add a module parameter that defaults to using this scheme.
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This should have the effect of squelching interop edge-cases where LPM
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noticeably degrades performance, and avoid the usual workaround where
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userspace manually disables it.
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Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>
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---
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drivers/usb/host/xhci.c | 8 ++++++--
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1 file changed, 6 insertions(+), 2 deletions(-)
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--- a/drivers/usb/host/xhci.c
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+++ b/drivers/usb/host/xhci.c
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@@ -39,6 +39,10 @@ static unsigned long long quirks;
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module_param(quirks, ullong, S_IRUGO);
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MODULE_PARM_DESC(quirks, "Bit flags for quirks to be enabled as default");
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+static int sandbag_lpm = 1;
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+module_param(sandbag_lpm, int, S_IRUGO | S_IWUSR);
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+MODULE_PARM_DESC(sandbag_lpm, "Use relaxed U1/U2 port LPM timeouts");
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+
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static bool td_on_ring(struct xhci_td *td, struct xhci_ring *ring)
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{
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struct xhci_segment *seg;
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@@ -4791,7 +4795,7 @@ static u16 xhci_calculate_u1_timeout(str
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}
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}
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- if (xhci->quirks & (XHCI_INTEL_HOST | XHCI_ZHAOXIN_HOST))
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+ if (sandbag_lpm || xhci->quirks & (XHCI_INTEL_HOST | XHCI_ZHAOXIN_HOST))
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timeout_ns = xhci_calculate_intel_u1_timeout(udev, desc);
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else
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timeout_ns = udev->u1_params.sel;
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@@ -4855,7 +4859,7 @@ static u16 xhci_calculate_u2_timeout(str
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}
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}
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- if (xhci->quirks & (XHCI_INTEL_HOST | XHCI_ZHAOXIN_HOST))
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+ if (sandbag_lpm || xhci->quirks & (XHCI_INTEL_HOST | XHCI_ZHAOXIN_HOST))
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timeout_ns = xhci_calculate_intel_u2_timeout(udev, desc);
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else
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timeout_ns = udev->u2_params.sel;
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