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 ECE7822579E; Fri, 31 Oct 2025 14:03:06 +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=1761919387; cv=none; b=TsTV5XIPbPYmeRCdgNaQOyW9QuhmV/jTv+Ah1oA0SW94okDxILnuBw0vuxM60Mn2SIMOO2rGkVJq06Vunb9A172gaRUthOKagns7J+ogknaE4ClESusXk+nC9aSHlUBqto2Ou5JIsXtVMb51z+JcCE/PC9E7TX2XkEUxgHo9K54= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761919387; c=relaxed/simple; bh=46FFnr9WLF9i9H0srZJRWF7kyywIMd+cnzId3IhG+1Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cq31Ftb/dc6FvNW7q8lFbOUr4gFh44XFOlrStJdA6WO8vvHZcHfFyOMECNk6DdLZ56WPD/aRQanV7TjuRLewO6RtxD4qSC76+NgjL7yxN96wUIYewQkfnTmBvKkTps4ZS9Nh7/W3HZBl1uI7snGpj4ePCeL2EnA29u8oAmQAHMA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=MyJAKxRc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="MyJAKxRc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6FF1AC4CEE7; Fri, 31 Oct 2025 14:03:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1761919386; bh=46FFnr9WLF9i9H0srZJRWF7kyywIMd+cnzId3IhG+1Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MyJAKxRcMDF7KxI7KS5alVN5JxeZT30QHsoL0+MZQyZnLUvZ2Ul8BHDWbyFERWn5w /UExs/wr2aFNbDU2pNzyQu7AbCz/FvK2BXMHEgzvOYbpbM21XbaCXqvFeTuPvnCMd7 DZy3VrIhxro7xcG4M8gwe5I8VxCv2850bmLxSdts= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Uday M Bhat , Mathias Nyman , Sasha Levin Subject: [PATCH 6.6 23/32] xhci: dbc: poll at different rate depending on data transfer activity Date: Fri, 31 Oct 2025 15:01:17 +0100 Message-ID: <20251031140043.003030045@linuxfoundation.org> X-Mailer: git-send-email 2.51.2 In-Reply-To: <20251031140042.387255981@linuxfoundation.org> References: <20251031140042.387255981@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ 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 Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci-dbgcap.c | 13 +++++++++++-- drivers/usb/host/xhci-dbgcap.h | 2 ++ 2 files changed, 13 insertions(+), 2 deletions(-) --- 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_db 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(struc 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(struc 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 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; --- 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];