From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-174.mta1.migadu.com (out-174.mta1.migadu.com [95.215.58.174]) (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 3E7DB2BAEC for ; Thu, 19 Dec 2024 02:54:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.174 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734576858; cv=none; b=RjQ28KDLdJ5gE5ZjQbZpbAkBTLzQiZfqt286/4WzJO5VmpL5rQT8j++pHG1bTZGanhMAYfhIH9xgbW7TRpmQMd8azbJVB/+A3ZDRrB4CiENnox6OspVprtQY0APp9DHqs4h7hYS8V2enIHWPotAsPpNlEHVYcejScG10JWtKdlM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734576858; c=relaxed/simple; bh=32JzfL8i2BcC8LmoH+P86BoEOMG5CHbdX1Um+cYz3gk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=hOkf1WX+IPEkAl2roL7xnbBGo7hQTpku+fEJYoV4zi612rovT/j1b5uM/Os+7WxqA50ByxOgsGCgohpq/4ruE6bRmAQtH5e5lNsgxZ/QdCHVo3TZTYBSPrJ1CIcZoHB6rC740NpqQsDaHvriCTSGMIu4m2mP8fyrdiYkoRTq1bM= 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=LYufAOki; arc=none smtp.client-ip=95.215.58.174 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="LYufAOki" Message-ID: <80e0813a-0651-41cf-a82d-776acbf1a5bc@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1734576854; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6lMvgcFdm6shecAfOp0/enr6sSGFabr8h+/cV806V2E=; b=LYufAOkiwude4trcf1KDzqZZuiwUZoqSndD7ugee1yJ/MfnkxOpfXUab07IVVcf9D2Jq1J lifBCezACrgwXWQz4SVl86MpZBVVl0nCG+geh6UYJ/qC4vu5fPfTS9DQjHOkeQBVh8fZMI Lb79fBVyhAS7Zw6I9obo8GJwVo7Nplc= Date: Thu, 19 Dec 2024 10:54:01 +0800 Precedence: bulk X-Mailing-List: loongarch@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH v2] loongarch/mm: disable WUC for pgprot_writecombine as same as ioremap_wc To: Icenowy Zheng , Xi Ruoyao , WANG Xuerui , Huacai Chen Cc: Andrew Morton , "Mike Rapoport (IBM)" , Baoquan He , "Matthew Wilcox (Oracle)" , David Hildenbrand , Zhen Lei , Thomas Gleixner , Zhihong Dong , loongarch@lists.linux.dev, linux-kernel@vger.kernel.org References: <20231009042841.635366-1-uwu@icenowy.me> <4f1af31b-15be-cb47-6b34-45de1b5696be@loongson.cn> <42b0e6f6-c2b5-49c6-b1f2-0200bef913da@xen0n.name> <3641d3fe-c2e7-868f-ab0d-3951c9a78b6d@loongson.cn> <8373ccfd93b0402caf9f5c06a2d9b93b3c0d0b49.camel@xry111.site> <1e0f2174a72011cb1c78eeecbbf82a4ff108bf8a.camel@icenowy.me> <1090f735-8252-453f-b6c8-0ec35881ff32@linux.dev> <932a9a93c00082645df465862231f6d8c91f3bf6.camel@icenowy.me> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Sui Jingfeng In-Reply-To: <932a9a93c00082645df465862231f6d8c91f3bf6.camel@icenowy.me> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 2024/12/18 20:43, Icenowy Zheng wrote: > For the fact of drm/ast's dramatical drop, it's because write to the > framebuffer can no longer be reordered. No, your understanding is wrong, very very wrong and a big wrong. It's not because it can't reorder the write. Rather, it's because that the CPU can't do write gathering and can't do burst write any more. So do you still think your patch is harmless? -- Best regards, Sui