From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 D6AFF12E7F for ; Wed, 11 Oct 2023 19:56:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="ZyVqHMVf" Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1D2CE94; Wed, 11 Oct 2023 12:56:41 -0700 (PDT) Received: from [10.192.9.210] (unknown [167.220.81.210]) by linux.microsoft.com (Postfix) with ESMTPSA id 988F920B74C0; Wed, 11 Oct 2023 12:56:40 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 988F920B74C0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1697054200; bh=TBZdQQUltpuV9HyLOh65oqRuciUQw/90/g0T1N3ig58=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=ZyVqHMVfdzF1nHDzGIyQs8vM2aDPTwCds7lZxmqJqjCOERCi0zfxlsR1mjY6tx/mY 3bDqV/Y/TqlTdddJjx62dNjea5bYxAji++z/ZLwt3bu0K7pssZR6JHCjRuYRZAkigi /B3Rix3JpJCc271GhTucwh8yg626j8LAl5b4ZiJ0= Message-ID: <42a5c36d-8b65-418f-9826-2808ab49d67a@linux.microsoft.com> Date: Wed, 11 Oct 2023 12:56:40 -0700 Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] acpi: Use access_width over register_width for system memory accesses Content-Language: en-US To: "Rafael J. Wysocki" Cc: Len Brown , "open list:ACPI" , open list References: <20230925180552.76071-1-jarredwhite@linux.microsoft.com> From: Jarred White In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-17.5 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,ENV_AND_HDR_SPF_MATCH,RCVD_IN_DNSWL_BLOCKED, SPF_HELO_PASS,SPF_PASS,USER_IN_DEF_DKIM_WL,USER_IN_DEF_SPF_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On 10/3/2023 11:50 AM, Rafael J. Wysocki wrote: > On Mon, Sep 25, 2023 at 8:06 PM Jarred White > wrote: >> To align with ACPI 6.3+, since bit_width can be any 8-bit value, we cannot >> depend on it being always on a clean 8b boundary. Instead, use access_width >> to determine the size and use the offset and width to shift and mask the >> bit swe want to read/write out. Make sure to add a check for system memory >> since pcc redefines the access_width to subspace id. > This is fine, but what if there are systems in the field where > bit_width is invalid, but they just happen to work because of the way > it is currently handled? For the kernel coding style issues, I will clean up for the v2 patch. On the invalid bit_width for systems out there in the field, do you have any suggestions on how to handle this particular scenario? Would it be appropriate to add a kernel parameter flag that can revert back to the previous implementation? P.S. Sorry for the HTML email. Thanks, Jarred