From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-175.mta0.migadu.com [91.218.175.175]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8DF4F3EC82E for ; Wed, 14 Oct 2026 09:13:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.175 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791969229; cv=none; b=WzIcyBSGChesM/HIX2zhkR300N6UBu+zAXnh90QSeR77a5Y82qJPfAC3+pwfcN8kdME7HHjs8n1KmAytyLLeTGIGLQnLpKnNjSfuO6JnJAF8jM57pRKYPQ8PNZeNS7FytzoUuhtINvoWUnrWxt/LHW24oIWU0QlhoBe4f3gK4H0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791969229; c=relaxed/simple; bh=oA4tFtMqs14J1OHw0hiEwTe8Icz1MDK1KJbF38IMy/U=; h=MIME-Version:Date:Content-Type:From:Message-ID:Subject:To:Cc: In-Reply-To:References; b=CV/5Nilm+nMzejmwyWxdELKkLFjhd1frrIaxaWCnAcJ6mqTLs6O0TFY84PvmubB4lbj0R2XWn1QHfzrdEyqLgc0oG2nrOh5CUsZJ/qSnahcNkhFYvra6fQeVvkXb78j3UnGu9z1KG44NSX3lyYUjw39vu+TscqJUje/+QZRmrh8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=IzusoGSn; arc=none smtp.client-ip=91.218.175.175 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="IzusoGSn" X-Envelope-To: linux-wireless@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=oA4tFtMqs14J1OHw0hiEwTe8Icz1MDK1KJbF38IMy/U=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1791969224; v=1; x=1792574024; b=IzusoGSnDPfv+DDZ94tQpTYjTRqM/HmU+O23gY0gIz9mLl5KhtUVB67K/9yahZrKKww6WhV4 sNCOV6foJaKpzxxQnX88MBtQnb3/1Y7N+7kIlXKdNBBFU+FvjdqLdTv4aZbSBghjRxOq7QJgTUj lZJf5iIqlfFZy/KWv80hmpfo= X-Envelope-To: linux-wireless@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id a13822d5b20933bb; Wed, 14 Oct 2026 09:13:44 +0000 X-Mizu-Trace-ID: a13822d5b20933bb X-Migadu-Flow: FLOW_OUT Precedence: bulk X-Mailing-List: linux-wireless@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Date: Wed, 14 Oct 2026 09:13:43 +0000 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: "Luka Gejak" Message-ID: <30d573f3dacbc0700605a29ef8ce1f4cd9c5dc8c@linux.dev> TLS-Required: No Subject: Re: [PATCH rtw-next v6 3/4] wifi: rtw88: sdio: Fix unhandled RX request interrupt storm To: "Alastair D'Silva" , linux-wireless@vger.kernel.org, "Ping-Ke Shih" , "Kalle Valo" Cc: "Martin Blumenstingl" , "Jernej Skrabec" , "Ulf Hansson" , linux-kernel@vger.kernel.org, "Alastair D'Silva" , stable@vger.kernel.org In-Reply-To: <20261014074426.2183095-4-alastair@d-silva.org> References: <20261014074426.2183095-1-alastair@d-silva.org> <20261014074426.2183095-4-alastair@d-silva.org> Hi Alastair, October 14, 2026 at 9:44 AM, "Alastair D'Silva" wr= ote: > On 3081-based SDIO chips (e.g. RTL8821CS), hardware does not automatica= lly > clear REG_SDIO_HISR_RX_REQUEST when the RX buffer is empty. Masking thi= s > bit out before writing back to HISR prevents it from being acknowledged= , > causing an infinite interrupt storm loop that locks up the system. In my opinion, I would reword this first sentance. Your own probe shows t= he bit does clear, post_drain_hisr comes back as 0x00800030 once the FIFO is empty, so what the hardware needs is the software acknowledge plus an empty FIFO. The old code masked the acknowledge out of the writeback so it never happened, which is the failure the second sentence describes. As written the first one reads as if the bit could never be cleared and the drain did not matter. The fix depends on the opposite reading. Best regards, Luka Gejak