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 289E63E00BB; Fri, 15 May 2026 16:05:04 +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=1778861104; cv=none; b=TzV194D9NR6pj7jCujViOoQ+vsW0Dl3GeGR6Pkusspmw14iBdO/FdHZSQTL9U2DcITYr6h6Rtm5nvI5GOiOpl4e9sPQbSiljIlmNNISlTiWoSyBZNKghxsTt1kcXDtHtY6VwH7JbW3WD1iJfFeMjwr+nGmlZrpYRtsTHrLvr1lo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778861104; c=relaxed/simple; bh=RLHNnJ+WiXCN1zh76sK3NGCeH0YLRyb61iRqIpK0fwk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UVc3Oe/gO85tOUHwfXesxJyWlcofLe3xeMGlSb32ux2CPfnaIG91kmRUXneviaj4rUB/WQQ6PyR5FXtqaloownSDTR70xQVJsEXIcp8GIPQekN/PWrYcdG5Ks6KIUw5HvOa95+ml9f5F8FYTMqt3KbbRt9UCSA0N0yLOf5hXXpw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=icid2glD; 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="icid2glD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B3A42C2BCB0; Fri, 15 May 2026 16:05:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778861104; bh=RLHNnJ+WiXCN1zh76sK3NGCeH0YLRyb61iRqIpK0fwk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=icid2glDYMfLi+lcvFsIuMvetYdgo2PdxkKQNKJHgjdyPEQz05bnOaEjq3tO9BVGd x/XXZJSM6KuryVrwRVLuulLhgD6PeTuLoxzr+xbAxJu86jYu/YIb94xr5o+cgtOQS9 7CXtBQVykRcnTBrHK8cvunCUqLGK+7Lp+h0oagPQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable , Aaro Koskinen Subject: [PATCH 6.6 198/474] USB: omap_udc: DMA: Dont enable burst 4 mode Date: Fri, 15 May 2026 17:45:07 +0200 Message-ID: <20260515154719.302293715@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260515154715.053014143@linuxfoundation.org> References: <20260515154715.053014143@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: 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 @@ -734,8 +734,6 @@ 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, @@ -757,8 +755,6 @@ 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); } }