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 53D8F23CE; Tue, 3 Dec 2024 16:06:10 +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=1733241970; cv=none; b=VbiE8Q/GKTbvqza4P15lq6DCfS0useM112lsZzxPPN++iEtuzq612MY8/f9N+N3I98yIbQxZbCmt749kMCrqfqGPB4zjuMfWuklK9XkMl+PtPjgA4hZukdTF0jh1Vj06q5gOnf0rkAPTbo75VGBfgXoy7gXWlcYKu3Cb9wrm5eY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733241970; c=relaxed/simple; bh=yfae5t2PM2KFj7Y+tf25kEW0Gheg/a7pS3rvPp8O37U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=T4N15FfdStYRYxDi/KqSOV9lRruAHPyxAzPhpciAOfCIitWgLoOo3kxSN5TmackJfS0hzRdxV8hQ4lRtXZL9KydVLLOpytFyparCGu9vIBCn4fovaEOfm32c+UPRCe2T3BeIDymh84CYk3v/HTM1oAGgb925FeRe/SnwWsQIINo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=X0tI5nGG; 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="X0tI5nGG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B77E9C4CECF; Tue, 3 Dec 2024 16:06:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1733241970; bh=yfae5t2PM2KFj7Y+tf25kEW0Gheg/a7pS3rvPp8O37U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=X0tI5nGGT7vr4AZf/GA5qvO4J7rXwE06bsy1tuyAWTo9BUQXgGBBxsotpiswlotvl dT1KyJaeEvaPQXQblkrl1jBe0IyTw8bwsH71doSCOJkOsiURAxcZ1SrziygGzf7Hcw Rxpg/5js26U144IWOci2ZTlVT6sSWWdyRqdMmiU0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Maxime Chevallier , Paolo Abeni , Sasha Levin Subject: [PATCH 6.12 569/826] net: stmmac: dwmac-socfpga: Set RX watchdog interrupt as broken Date: Tue, 3 Dec 2024 15:44:56 +0100 Message-ID: <20241203144805.945850583@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241203144743.428732212@linuxfoundation.org> References: <20241203144743.428732212@linuxfoundation.org> User-Agent: quilt/0.67 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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Maxime Chevallier [ Upstream commit 407618d66dba55e7db1278872e8be106808bbe91 ] On DWMAC3 and later, there's a RX Watchdog interrupt that's used for interrupt coalescing. It's known to be buggy on some platforms, and dwmac-socfpga appears to be one of them. Changing the interrupt coalescing from ethtool doesn't appear to have any effect here. Without disabling RIWT (Received Interrupt Watchdog Timer, I believe...), we observe latencies while receiving traffic that amount to around ~0.4ms. This was discovered with NTP but can be easily reproduced with a simple ping. Without this patch : 64 bytes from 192.168.5.2: icmp_seq=1 ttl=64 time=0.657 ms With this patch : 64 bytes from 192.168.5.2: icmp_seq=1 ttl=64 time=0.254 ms Fixes: 801d233b7302 ("net: stmmac: Add SOCFPGA glue driver") Signed-off-by: Maxime Chevallier Link: https://patch.msgid.link/20241122141256.764578-1-maxime.chevallier@bootlin.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c index fdb4c773ec98a..e897b49aa9e05 100644 --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c @@ -486,6 +486,8 @@ static int socfpga_dwmac_probe(struct platform_device *pdev) plat_dat->pcs_exit = socfpga_dwmac_pcs_exit; plat_dat->select_pcs = socfpga_dwmac_select_pcs; + plat_dat->riwt_off = 1; + ret = stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res); if (ret) return ret; -- 2.43.0