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 F300F3B1EE2; Tue, 12 May 2026 17:43:40 +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=1778607821; cv=none; b=V8RxwfwEV85qTfI6USB/sYrDbfA8KzCbZeGgZV6PDa9HV2ekZOF0cQs8StfUnQgHZ2yr/sD/XdK9HCHWDv3sf/1qugQznb7SpVH59XhPwzGFIZUnlZJAcUspZ3wHqyhZK9mRAEWH/pgNqZgHl1LFXq4KLNkCGvOxj4F7iIv/Y2c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778607821; c=relaxed/simple; bh=JHFJ9y+N9rPOYo29dVlWQ7S6QNXyhUdcGykB0o+x5A8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=E+ON+XR5rhNFcSuAaZRd7MttJ+G4R7ivbc+FLhHflAd24o8goVNNMl8ppXYxEMcyaGD04yGrY2RJ0wM74tE4sa0sqCEJgSV2fKDwNXSO7TiLNVWtEZ/o2+mZk0Th3yFKcg+tgjEoHqslI5z6VR/ZUNSanz13u4o9qPIlVSkOX2Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=15p/gDBT; 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="15p/gDBT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85EEEC2BCB0; Tue, 12 May 2026 17:43:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778607820; bh=JHFJ9y+N9rPOYo29dVlWQ7S6QNXyhUdcGykB0o+x5A8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=15p/gDBTTdi/Gu45EJ/qBfLoFbRO0eTWwYvocQ2qWiVVL76sAq8kUZJ9vMk5qDgpN yk9oXsf1VgBiTeeUH1kmigmygJSx8UmBfEhuGBNlWbj2v5D2Dn3lhsrVwtVaKCPAph s4isbMD27uNPx8m7GIPg+aCOCcp9NuPuwphsoe1k= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable , Aaro Koskinen Subject: [PATCH 6.12 047/206] USB: omap_udc: DMA: Dont enable burst 4 mode Date: Tue, 12 May 2026 19:38:19 +0200 Message-ID: <20260512173933.833279225@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260512173932.810559588@linuxfoundation.org> References: <20260512173932.810559588@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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Aaro Koskinen commit 3f91484f6c13c434bd573ca6b6779c26adb0ddab upstream. Commit 65111084c63d7 ("USB: more omap_udc updates (dma and omap1710)") added setting for DMA burst 4 mode. But I think this should be undone for two reasons: - It breaks DMA on 15xx boards - transfers just silently stall. - On newer OMAP1 boards, like Nokia 770 (omap1710), there is no measurable performance impact when testing TCP throughput with g_ether with large 15000 byte MTU size. It's also worth noting that when the original change was made, the OMAP_DMA_DATA_BURST_4 handling in arch/arm/plat-omap/dma.c was broken, and actually resulted in the same as the OMAP_DMA_DATA_BURST_DIS i.e. burst disabled. This was fixed not until a couple kernel releases later in an unrelated commit 1a8bfa1eb998a ("[ARM] 3142/1: OMAP 2/5: Update files common to omap1 and omap2"). So based on this it seems there was never really a very good reason to enable this burst mode in omap_udc, so remove it now to allow 15xx DMA to work again (it provides 2x throughput compared to PIO mode). Fixes: 65111084c63d ("[PATCH] USB: more omap_udc updates (dma and omap1710)") Cc: stable Signed-off-by: Aaro Koskinen Link: https://patch.msgid.link/ad06qHLclWHeSGnV@darkstar.musicnaut.iki.fi Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/udc/omap_udc.c | 4 ---- 1 file changed, 4 deletions(-) --- a/drivers/usb/gadget/udc/omap_udc.c +++ b/drivers/usb/gadget/udc/omap_udc.c @@ -732,8 +732,6 @@ static void dma_channel_claim(struct oma if (status == 0) { omap_writew(reg, UDC_TXDMA_CFG); /* EMIFF or SDRC */ - omap_set_dma_src_burst_mode(ep->lch, - OMAP_DMA_DATA_BURST_4); omap_set_dma_src_data_pack(ep->lch, 1); /* TIPB */ omap_set_dma_dest_params(ep->lch, @@ -755,8 +753,6 @@ static void dma_channel_claim(struct oma UDC_DATA_DMA, 0, 0); /* EMIFF or SDRC */ - omap_set_dma_dest_burst_mode(ep->lch, - OMAP_DMA_DATA_BURST_4); omap_set_dma_dest_data_pack(ep->lch, 1); } }