From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F035D606A324 for ; Fri, 23 Oct 2026 20:15:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=t3DVKKMv; dkim=fail reason="signature verification failed" (2048-bit key, unprotected) header.d=bues.ch header.i=@bues.ch header.a=rsa-sha256 header.s=main header.b=faQCOktY DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: MIME-Version:References:In-Reply-To:Message-ID:Subject:Cc:To:From:Date: Reply-To:Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date :Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Unsubscribe-Post:List-Owner; bh=QbD5EZsqQkLfg0NP2IZF3o7rlRVDc5RCd0zOF/YZFX4=; b=t3DVKKMvYhL3fncFqcySY/DYVd uDt36Rfhc7ae9j62QtABHJcCtdX1vQVrCeEo3KU5ZNdDM32I29ctRtXKEAIBregNpGbj0bPK6EnCo FG6kO9xaFCJDQZNJnDuAGix2Pbn2KAbRky0vGypmRG/IHi/d5B/m9FeeG0x71OQIydGb3+lIMJYDQ c7Kn8XSLYMhT5BaGJh/vtkqECBg7wYC1mJ8dAC/1ABZWwUPSjFh28KmmwXCEFPujhQ2GYzQRxZAVr v58av9Jf8dM8+ibClHxu+i8U74XR4HtCLWnPUk+wsvozy10QQfha2YLkohmyJTM1+kZziqtCCBMqU 1vKDjIjg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xKLfb-0000000Guv4-2zqT; Fri, 23 Oct 2026 20:15:19 +0000 Received: from bues.ch ([2a01:4f8:1c0c:6e7f::1] helo=mail.bues.ch) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xKLfU-0000000GuuV-28K2 for b43-dev@lists.infradead.org; Fri, 23 Oct 2026 20:15:14 +0000 Date: Fri, 23 Oct 2026 22:14:24 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bues.ch; s=main; t=1792786506; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=m/PMCHPO/jr5fAoLR41c5oEssMjic1/6mLM+L0/ZmP4=; b=faQCOktYlanW4afHud0z/jvY8YQ3Tmv0i2ALoSWK2H8If1W+1uJVT7tGEiHoYVYqK1RBO+ rR1YQhmJtJ3NVUphzwW1X76OekfXWPY9+Z1BNPZrrNHb1S1c6Mw0NJKrryPE8ctkXF5mWB DMV8mOk7hWmENQPPj2am++9RrEU4+yAdDU/BvkAD/1Vv4FoKApUnQERaY6Tw2PfoiD4+8p MIasi1nbRa5Jb0kImelCHnxPQidwk3gbnyQA1gESF5Hqos0eM73UsMGgHSyJuu70pjBNFG pY8Nj/XLzX/Iz1h5LYjTnShAocH6ZJoBLNy4ipiyj4bZrrQ6P3HlVr8lgNavQg== From: Michael =?UTF-8?B?QsO8c2No?= To: Rosen Penev Cc: linux-wireless@vger.kernel.org, b43-dev@lists.infradead.org (open list:B43 WIRELESS DRIVER), linux-kernel@vger.kernel.org (open list) Subject: Re: [PATCH wireless] wifi: b43: map the RX buffers DMA_BIDIRECTIONAL Message-ID: <20261023221424.2722795e@barney> In-Reply-To: <20261023190653.70741-1-rosenp@gmail.com> References: <20261023190653.70741-1-rosenp@gmail.com> X-Mailer: Claws Mail 4.4.0 (GTK 3.24.52; x86_64-pc-linux-gnu) X-Archived-By: MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261023_131512_766378_66DF2BFB X-CRM114-Status: GOOD ( 18.96 ) X-Spam-Score: -2.1 (--) X-BeenThere: b43-dev@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: b43/b43legacy Linux driver discussions List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============5605471517119407258==" Sender: "b43-dev" X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 --===============5605471517119407258== Content-Type: multipart/signed; boundary="Sig_/EtGF2lcPb61ELDgqh=HK/KQ"; protocol="application/pgp-signature"; micalg=pgp-sha512 --Sig_/EtGF2lcPb61ELDgqh=HK/KQ Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Quite honestly, to me this looks like a lot of AI slop is sent to b43 these= days. Can you please slow down your submissions so that actual people get a chanc= e to review the stuff? Thanks! --=20 Michael B=C3=BCsch https://bues.ch/ On Fri, 23 Oct 2026 12:06:53 -0700 Rosen Penev wrote: > b43 poisons each RX buffer before it hands it to the device, and drops > a buffer that still carries the poison, as the device sometimes skips > one. The RX buffers are mapped and synced DMA_FROM_DEVICE. On a > non-coherent CPU like the BCM4716 or the BCM4708, the map and the sync > for the device then only invalidate the cache, so the poison written > just before never reaches memory. A skipped buffer is read as whatever > the memory held before, for a recycled buffer the data of its previous > use: garbage frames, or a length that sends dma_rx() into its path for > frames spanning several buffers. >=20 > Map, sync and unmap the RX buffers DMA_BIDIRECTIONAL, so that the > poison is written back before the device gets the buffer. >=20 > Reported on a Netgear R6400 (BCM4708, BCM4331). >=20 > Fixes: cf68636a9773 ("b43: Refresh RX poison on buffer recycling") > Signed-off-by: Rosen Penev > --- > drivers/net/wireless/broadcom/b43/dma.c | 14 ++++++++++---- > 1 file changed, 10 insertions(+), 4 deletions(-) >=20 > diff --git a/drivers/net/wireless/broadcom/b43/dma.c b/drivers/net/wirele= ss/broadcom/b43/dma.c > index 05da6987a845..c8585c6dff37 100644 > --- a/drivers/net/wireless/broadcom/b43/dma.c > +++ b/drivers/net/wireless/broadcom/b43/dma.c > @@ -353,8 +353,14 @@ static inline > dmaaddr =3D dma_map_single(ring->dev->dev->dma_dev, > buf, len, DMA_TO_DEVICE); > } else { > + /* > + * Not DMA_FROM_DEVICE: on a non-coherent CPU, the map and > + * the sync for the device would then only invalidate the > + * cache, and the poison of b43_poison_rx_buffer() would > + * never reach memory. > + */ > dmaaddr =3D dma_map_single(ring->dev->dev->dma_dev, > - buf, len, DMA_FROM_DEVICE); > + buf, len, DMA_BIDIRECTIONAL); > } > =20 > return dmaaddr; > @@ -369,7 +375,7 @@ static inline > addr, len, DMA_TO_DEVICE); > } else { > dma_unmap_single(ring->dev->dev->dma_dev, > - addr, len, DMA_FROM_DEVICE); > + addr, len, DMA_BIDIRECTIONAL); > } > } > =20 > @@ -379,7 +385,7 @@ static inline > { > B43_WARN_ON(ring->tx); > dma_sync_single_for_cpu(ring->dev->dev->dma_dev, > - addr, len, DMA_FROM_DEVICE); > + addr, len, DMA_BIDIRECTIONAL); > } > =20 > static inline > @@ -388,7 +394,7 @@ static inline > { > B43_WARN_ON(ring->tx); > dma_sync_single_for_device(ring->dev->dev->dma_dev, > - addr, len, DMA_FROM_DEVICE); > + addr, len, DMA_BIDIRECTIONAL); > } > =20 > static inline --Sig_/EtGF2lcPb61ELDgqh=HK/KQ Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEEihRzkKVZOnT2ipsS9TK+HZCNiw4FAmrbwCAACgkQ9TK+HZCN iw5vLA/8DgP3NmxzLRRtxhfbKFM0SPl36d7r97iUfi3lnPyV2HiDvZR6R2AIK7V8 FmSgoLZTk73e29ildUC5bzampS/b2Ds220dSxNNvEE1dkwxjatPNQvR69GnRnitu Jtzg51WaJxm4CSzOxEpaB+IZbpoW+hC+7hNFZh5gflkfXjocPa14o/mCK3sWZyvv kSHXf32dRPZpz4S92feA8Ll88QvfaNRpLpWNu6AyoFYXFxn6CYOkYq7bbidcNCYz 43zatonqNJ/WhjlZ/94XYTqjCFazz4+htEF6Ztp4u5xExX8eWz8eJzhq34gvd5nW bd20jVnC6A8Away6q81wD5wtFal2Fa5mpyy6F8YVjSrAW6NmE+x6h/op0a1l0Vw1 N1j+aibPst8NJhXQ9+h4KfDEh5t4nVohpaTEia4wzNZOtQPEYoUyzK2mh0/KiQbc 1xOHEXcjkIsZ0RlzEQ3YDNqM9m7Q9t2HS4hrwfMGdWlW0TxmhbIEBSQHhySQmtvF TEI4fTeTW8Xg5x+U2hdU4hkv+Knq5AAavykNBU9Clg+jqhq3OZIbsEY3x+kuJafJ W0wzJNi4cPwQDs4q5lJOki++s6u5fC3wWmgOomzJYmMxEDmYcgr2VmdyrvNQeTu7 H6OsBVVrPQ9942VwW6LzuLyERgFScOOx4UYEPCMqfBHbnPSWQrs= =nu7c -----END PGP SIGNATURE----- --Sig_/EtGF2lcPb61ELDgqh=HK/KQ-- --===============5605471517119407258== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ b43-dev mailing list b43-dev@lists.infradead.org http://lists.infradead.org/mailman/listinfo/b43-dev --===============5605471517119407258==--