From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3C46030ACF4 for ; Mon, 27 Oct 2025 16:29:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761582562; cv=none; b=tTjucqKy9+Utq3eRkmasxMWGHJdHomD5jE7HdtyaFXEgd6hlhP50EU5hSXgqMtsGUXI3d9YPbg8HY2lpaYq3i0oz7hNnsj6Fi3EVnWIdBn2m1P8uuYSbxcQLRoL7dNXeD5gj91TtlKlvehyl9Y2ejMUAV3DKDnLmhexuicPIuT4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761582562; c=relaxed/simple; bh=BDbqPXmvb6zsC+fTq7iA+b8VOU9KNaHtfeRYWjsagAI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CDtaoIDt5Ht8i7Jhr/NoEmY0hMCC9Pm1PRP5W6Z3C4CCQ1N8DJEZPlZNnEW2izecCcNoYGHw7JHB7KebIA6LhZVWJcUN1s4bolrLD5pw1LxNTh/ZROZQRWIHB3TCO84s0gzr4eUn+xlbOk//LZSAcZI04ZGAgR3e98ysqOt68as= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=U4EHiHFT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="U4EHiHFT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F84FC4CEF1; Mon, 27 Oct 2025 16:29:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761582562; bh=BDbqPXmvb6zsC+fTq7iA+b8VOU9KNaHtfeRYWjsagAI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U4EHiHFTMSipbv2wWZ4jWk2rFCLjnMwO4yaTz6C2LvjoKaJOEIAywK74zUo7GcyJN ybIZ3cbzwIlOdGh8s1OUvtNtzSqrZYPpw2key4KCP+QWKLA4pPQrVbWHnFmm+S+mUf NxDjaNhgSLaADHERwgwMzm8j5tpVK8MaagZseNITgGTp81uHsatWy6Qi4ImVlwcItn wUY61cDQgFAyeMTL0FKDQ99Q5gVXYTaiQUyYY336QBj1cAyZUiwjQW9UNTwey/hrf8 iYJFdLOIUKpgFnKDiYqUiVciwMuxVmkocUrLBhinVR3Q27u/bQb3cCRHCUD8zKXamI 2reXGBjmVkWIg== From: Sasha Levin To: stable@vger.kernel.org Cc: Mathias Nyman , Uday M Bhat , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH 6.6.y 1/5] xhci: dbc: poll at different rate depending on data transfer activity Date: Mon, 27 Oct 2025 12:29:15 -0400 Message-ID: <20251027162919.577996-1-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <2025102712-unearned-duplicate-8c3b@gregkh> References: <2025102712-unearned-duplicate-8c3b@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Mathias Nyman [ Upstream commit fb18e5bb96603cc79d97f03e4c05f3992cf28624 ] DbC driver starts polling for events immediately when DbC is enabled. The current polling interval is 1ms, which keeps the CPU busy, impacting power management even when there are no active data transfers. Solve this by polling at a slower rate, with a 64ms interval as default until a transfer request is queued, or if there are still are pending unhandled transfers at event completion. Tested-by: Uday M Bhat Signed-off-by: Mathias Nyman Link: https://lore.kernel.org/r/20240229141438.619372-9-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman Stable-dep-of: f3d12ec847b9 ("xhci: dbc: fix bogus 1024 byte prefix if ttyDBC read races with stall event") Signed-off-by: Sasha Levin --- drivers/usb/host/xhci-dbgcap.c | 13 +++++++++++-- drivers/usb/host/xhci-dbgcap.h | 2 ++ 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/usb/host/xhci-dbgcap.c b/drivers/usb/host/xhci-dbgcap.c index 764657070883c..79d70e5aaa92c 100644 --- a/drivers/usb/host/xhci-dbgcap.c +++ b/drivers/usb/host/xhci-dbgcap.c @@ -665,7 +665,8 @@ static int xhci_dbc_start(struct xhci_dbc *dbc) return ret; } - return mod_delayed_work(system_wq, &dbc->event_work, 1); + return mod_delayed_work(system_wq, &dbc->event_work, + msecs_to_jiffies(dbc->poll_interval)); } static void xhci_dbc_stop(struct xhci_dbc *dbc) @@ -964,8 +965,10 @@ static void xhci_dbc_handle_events(struct work_struct *work) enum evtreturn evtr; struct xhci_dbc *dbc; unsigned long flags; + unsigned int poll_interval; dbc = container_of(to_delayed_work(work), struct xhci_dbc, event_work); + poll_interval = dbc->poll_interval; spin_lock_irqsave(&dbc->lock, flags); evtr = xhci_dbc_do_handle_events(dbc); @@ -981,13 +984,18 @@ static void xhci_dbc_handle_events(struct work_struct *work) dbc->driver->disconnect(dbc); break; case EVT_DONE: + /* set fast poll rate if there are pending data transfers */ + if (!list_empty(&dbc->eps[BULK_OUT].list_pending) || + !list_empty(&dbc->eps[BULK_IN].list_pending)) + poll_interval = 1; break; default: dev_info(dbc->dev, "stop handling dbc events\n"); return; } - mod_delayed_work(system_wq, &dbc->event_work, 1); + mod_delayed_work(system_wq, &dbc->event_work, + msecs_to_jiffies(poll_interval)); } static ssize_t dbc_show(struct device *dev, @@ -1242,6 +1250,7 @@ xhci_alloc_dbc(struct device *dev, void __iomem *base, const struct dbc_driver * dbc->idVendor = DBC_VENDOR_ID; dbc->bcdDevice = DBC_DEVICE_REV; dbc->bInterfaceProtocol = DBC_PROTOCOL; + dbc->poll_interval = DBC_POLL_INTERVAL_DEFAULT; if (readl(&dbc->regs->control) & DBC_CTRL_DBC_ENABLE) goto err; diff --git a/drivers/usb/host/xhci-dbgcap.h b/drivers/usb/host/xhci-dbgcap.h index 2de0dc49a3e9f..d165bafecd98f 100644 --- a/drivers/usb/host/xhci-dbgcap.h +++ b/drivers/usb/host/xhci-dbgcap.h @@ -93,6 +93,7 @@ struct dbc_ep { #define DBC_QUEUE_SIZE 16 #define DBC_WRITE_BUF_SIZE 8192 +#define DBC_POLL_INTERVAL_DEFAULT 64 /* milliseconds */ /* * Private structure for DbC hardware state: @@ -139,6 +140,7 @@ struct xhci_dbc { enum dbc_state state; struct delayed_work event_work; + unsigned int poll_interval; /* ms */ unsigned resume_required:1; struct dbc_ep eps[2]; -- 2.51.0