From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 8C4032EF652; Sat, 30 May 2026 18:32:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780165929; cv=none; b=Zr5pOlYot7Vm0l8/oLOgq5q2kGdoR5wDuYm8J2K3kgjFw7rk4ctsr36XWssCfrZfO58x08/P6gko1fhSfRyN0jIwgZU1pGMgjxrNKGWyz9TDJ8/tPZG/OdC/6C0OOdUUMD7T6JO7Uaj5rkKpucvyxsD8C+IE0bxHDzD5H7LhlQI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780165929; c=relaxed/simple; bh=ZqBNJh+eqieTx0Erc00F3lDv2YVcbIbejAefWKLX/gY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IDLjYxQ/LnZq9f6A7XsSIe04ajCY8BYUbJ9xnm0Kh0EQTKJueiRzuY8PcCDnIEl6uQKGxh0GGdXmav5G+SLP7avohgTusOcPjAu7I0x1kUXynSGXSB4964LK8Px1LoWS4MWi9LH1Q7tL5fi6y4at+ycKSr3SrPAJ14bP0DsVVoA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=wnVG7E2e; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="wnVG7E2e" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 990E61F00893; Sat, 30 May 2026 18:32:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780165928; bh=Uu7myFk927t1dp2Ly0IVkaNIobtlltCnMiUMYq7W7nM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=wnVG7E2eWkiK/9y+u0zVFaXmU33AFiwMZf/4d9bPjsa4tvqpp1ZBJqAAQp/yUPmss MvYwURVEbnimQbwOC2hn8Ry+MGmOFi2yXaoIPRrf/MIZRFqLdiOqcxtyG3DubswU6f FP5z3jSeNj7p0OVdMVsDGyHcQTrR73GI3mjUwoX4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable , Aaro Koskinen Subject: [PATCH 5.10 224/589] USB: omap_udc: DMA: Dont enable burst 4 mode Date: Sat, 30 May 2026 18:01:45 +0200 Message-ID: <20260530160230.868812671@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160224.570625122@linuxfoundation.org> References: <20260530160224.570625122@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-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 @@ -731,8 +731,6 @@ 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, @@ -754,8 +752,6 @@ 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); } }