From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5C51EC04A6B for ; Thu, 9 May 2019 01:48:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2A17420675 for ; Thu, 9 May 2019 01:48:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726607AbfEIBsq (ORCPT ); Wed, 8 May 2019 21:48:46 -0400 Received: from gateway33.websitewelcome.com ([192.185.146.80]:11720 "EHLO gateway33.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725832AbfEIBsq (ORCPT ); Wed, 8 May 2019 21:48:46 -0400 Received: from cm14.websitewelcome.com (cm14.websitewelcome.com [100.42.49.7]) by gateway33.websitewelcome.com (Postfix) with ESMTP id EC31A22545 for ; Wed, 8 May 2019 20:48:44 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id OYAuhxyOt2qH7OYAuhFaDv; Wed, 08 May 2019 20:48:44 -0500 X-Authority-Reason: nr=8 Received: from [189.250.119.7] (port=58166 helo=[192.168.1.76]) by gator4166.hostgator.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.91) (envelope-from ) id 1hOYAu-004A0S-Hb; Wed, 08 May 2019 20:48:44 -0500 To: Darren Hart Cc: "Lee, Chun-Yi" , Andy Shevchenko , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, Kees Cook References: <20190508164934.GA20064@embeddedor> <20190508230645.GB32286@wrath> From: "Gustavo A. R. Silva" Openpgp: preference=signencrypt Autocrypt: addr=gustavo@embeddedor.com; keydata= mQINBFssHAwBEADIy3ZoPq3z5UpsUknd2v+IQud4TMJnJLTeXgTf4biSDSrXn73JQgsISBwG 2Pm4wnOyEgYUyJd5tRWcIbsURAgei918mck3tugT7AQiTUN3/5aAzqe/4ApDUC+uWNkpNnSV tjOx1hBpla0ifywy4bvFobwSh5/I3qohxDx+c1obd8Bp/B/iaOtnq0inli/8rlvKO9hp6Z4e DXL3PlD0QsLSc27AkwzLEc/D3ZaqBq7ItvT9Pyg0z3Q+2dtLF00f9+663HVC2EUgP25J3xDd 496SIeYDTkEgbJ7WYR0HYm9uirSET3lDqOVh1xPqoy+U9zTtuA9NQHVGk+hPcoazSqEtLGBk YE2mm2wzX5q2uoyptseSNceJ+HE9L+z1KlWW63HhddgtRGhbP8pj42bKaUSrrfDUsicfeJf6 m1iJRu0SXYVlMruGUB1PvZQ3O7TsVfAGCv85pFipdgk8KQnlRFkYhUjLft0u7CL1rDGZWDDr NaNj54q2CX9zuSxBn9XDXvGKyzKEZ4NY1Jfw+TAMPCp4buawuOsjONi2X0DfivFY+ZsjAIcx qQMglPtKk/wBs7q2lvJ+pHpgvLhLZyGqzAvKM1sVtRJ5j+ARKA0w4pYs5a5ufqcfT7dN6TBk LXZeD9xlVic93Ju08JSUx2ozlcfxq+BVNyA+dtv7elXUZ2DrYwARAQABtCxHdXN0YXZvIEEu IFIuIFNpbHZhIDxndXN0YXZvQGVtYmVkZGVkb3IuY29tPokCPQQTAQgAJwUCWywcDAIbIwUJ CWYBgAULCQgHAgYVCAkKCwIEFgIDAQIeAQIXgAAKCRBHBbTLRwbbMZ6tEACk0hmmZ2FWL1Xi l/bPqDGFhzzexrdkXSfTTZjBV3a+4hIOe+jl6Rci/CvRicNW4H9yJHKBrqwwWm9fvKqOBAg9 obq753jydVmLwlXO7xjcfyfcMWyx9QdYLERTeQfDAfRqxir3xMeOiZwgQ6dzX3JjOXs6jHBP cgry90aWbaMpQRRhaAKeAS14EEe9TSIly5JepaHoVdASuxklvOC0VB0OwNblVSR2S5i5hSsh ewbOJtwSlonsYEj4EW1noQNSxnN/vKuvUNegMe+LTtnbbocFQ7dGMsT3kbYNIyIsp42B5eCu JXnyKLih7rSGBtPgJ540CjoPBkw2mCfhj2p5fElRJn1tcX2McsjzLFY5jK9RYFDavez5w3lx JFgFkla6sQHcrxH62gTkb9sUtNfXKucAfjjCMJ0iuQIHRbMYCa9v2YEymc0k0RvYr43GkA3N PJYd/vf9vU7VtZXaY4a/dz1d9dwIpyQARFQpSyvt++R74S78eY/+lX8wEznQdmRQ27kq7BJS R20KI/8knhUNUJR3epJu2YFT/JwHbRYC4BoIqWl+uNvDf+lUlI/D1wP+lCBSGr2LTkQRoU8U 64iK28BmjJh2K3WHmInC1hbUucWT7Swz/+6+FCuHzap/cjuzRN04Z3Fdj084oeUNpP6+b9yW e5YnLxF8ctRAp7K4yVlvA7kCDQRbLBwMARAAsHCE31Ffrm6uig1BQplxMV8WnRBiZqbbsVJB H1AAh8tq2ULl7udfQo1bsPLGGQboJSVN9rckQQNahvHAIK8ZGfU4Qj8+CER+fYPp/MDZj+t0 DbnWSOrG7z9HIZo6PR9z4JZza3Hn/35jFggaqBtuydHwwBANZ7A6DVY+W0COEU4of7CAahQo 5NwYiwS0lGisLTqks5R0Vh+QpvDVfuaF6I8LUgQR/cSgLkR//V1uCEQYzhsoiJ3zc1HSRyOP otJTApqGBq80X0aCVj1LOiOF4rrdvQnj6iIlXQssdb+WhSYHeuJj1wD0ZlC7ds5zovXh+FfF l5qH5RFY/qVn3mNIVxeO987WSF0jh+T5ZlvUNdhedGndRmwFTxq2Li6GNMaolgnpO/CPcFpD jKxY/HBUSmaE9rNdAa1fCd4RsKLlhXda+IWpJZMHlmIKY8dlUybP+2qDzP2lY7kdFgPZRU+e zS/pzC/YTzAvCWM3tDgwoSl17vnZCr8wn2/1rKkcLvTDgiJLPCevqpTb6KFtZosQ02EGMuHQ I6Zk91jbx96nrdsSdBLGH3hbvLvjZm3C+fNlVb9uvWbdznObqcJxSH3SGOZ7kCHuVmXUcqoz ol6ioMHMb+InrHPP16aVDTBTPEGwgxXI38f7SUEn+NpbizWdLNz2hc907DvoPm6HEGCanpcA EQEAAYkCJQQYAQgADwUCWywcDAIbDAUJCWYBgAAKCRBHBbTLRwbbMdsZEACUjmsJx2CAY+QS UMebQRFjKavwXB/xE7fTt2ahuhHT8qQ/lWuRQedg4baInw9nhoPE+VenOzhGeGlsJ0Ys52sd XvUjUocKgUQq6ekOHbcw919nO5L9J2ejMf/VC/quN3r3xijgRtmuuwZjmmi8ct24TpGeoBK4 WrZGh/1hAYw4ieARvKvgjXRstcEqM5thUNkOOIheud/VpY+48QcccPKbngy//zNJWKbRbeVn imua0OpqRXhCrEVm/xomeOvl1WK1BVO7z8DjSdEBGzbV76sPDJb/fw+y+VWrkEiddD/9CSfg fBNOb1p1jVnT2mFgGneIWbU0zdDGhleI9UoQTr0e0b/7TU+Jo6TqwosP9nbk5hXw6uR5k5PF 8ieyHVq3qatJ9K1jPkBr8YWtI5uNwJJjTKIA1jHlj8McROroxMdI6qZ/wZ1ImuylpJuJwCDC ORYf5kW61fcrHEDlIvGc371OOvw6ejF8ksX5+L2zwh43l/pKkSVGFpxtMV6d6J3eqwTafL86 YJWH93PN+ZUh6i6Rd2U/i8jH5WvzR57UeWxE4P8bQc0hNGrUsHQH6bpHV2lbuhDdqo+cM9eh GZEO3+gCDFmKrjspZjkJbB5Gadzvts5fcWGOXEvuT8uQSvl+vEL0g6vczsyPBtqoBLa9SNrS VtSixD1uOgytAP7RWS474w== Subject: Re: [PATCH] platform/x86: acer-wmi: Mark expected switch fall-throughs Message-ID: Date: Wed, 8 May 2019 20:48:43 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190508230645.GB32286@wrath> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 189.250.119.7 X-Source-L: No X-Exim-ID: 1hOYAu-004A0S-Hb X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: ([192.168.1.76]) [189.250.119.7]:58166 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 5 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Darren, Please, see my comments below... On 5/8/19 6:06 PM, Darren Hart wrote: > On Wed, May 08, 2019 at 11:49:34AM -0500, Gustavo A. R. Silva wrote: >> In preparation to enabling -Wimplicit-fallthrough, mark switch >> cases where we are expecting to fall through. >> >> This patch fixes the following warnings: >> >> drivers/platform/x86/acer-wmi.c: In function ‘set_u32’: >> drivers/platform/x86/acer-wmi.c:1378:33: warning: this statement may fall through [-Wimplicit-fallthrough=] >> if (cap == ACER_CAP_WIRELESS || >> ^ >> drivers/platform/x86/acer-wmi.c:1386:3: note: here >> case ACER_WMID: >> ^~~~ >> drivers/platform/x86/acer-wmi.c:1393:12: warning: this statement may fall through [-Wimplicit-fallthrough=] >> else if (wmi_has_guid(WMID_GUID2)) >> ^ >> drivers/platform/x86/acer-wmi.c:1395:3: note: here >> default: >> ^~~~~~~ >> drivers/platform/x86/acer-wmi.c: In function ‘get_u32’: >> drivers/platform/x86/acer-wmi.c:1340:6: warning: this statement may fall through [-Wimplicit-fallthrough=] >> if (cap == ACER_CAP_MAILLED) { >> ^ >> drivers/platform/x86/acer-wmi.c:1344:2: note: here >> case ACER_WMID: >> ^~~~ >> drivers/platform/x86/acer-wmi.c: In function ‘WMID_get_u32’: >> drivers/platform/x86/acer-wmi.c:1013:6: warning: this statement may fall through [-Wimplicit-fallthrough=] >> if (quirks->mailled == 1) { >> ^ >> drivers/platform/x86/acer-wmi.c:1018:2: note: here >> default: >> ^~~~~~~ >> >> Warning level 3 was used: -Wimplicit-fallthrough=3 >> >> This patch is part of the ongoing efforts to enable >> -Wimplicit-fallthrough. >> >> Signed-off-by: Gustavo A. R. Silva >> --- >> drivers/platform/x86/acer-wmi.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/drivers/platform/x86/acer-wmi.c b/drivers/platform/x86/acer-wmi.c >> index fcfeadd1301f..bd87f9037f95 100644 >> --- a/drivers/platform/x86/acer-wmi.c >> +++ b/drivers/platform/x86/acer-wmi.c >> @@ -1015,6 +1015,7 @@ static acpi_status WMID_get_u32(u32 *value, u32 cap) >> *value = tmp & 0x1; >> return 0; >> } >> + /* fall through */ >> default: >> return AE_ERROR; >> } >> @@ -1341,6 +1342,7 @@ static acpi_status get_u32(u32 *value, u32 cap) >> status = AMW0_get_u32(value, cap); >> break; >> } >> + /* fall through */ > > This doesn't strike me as obviously the right thing to do here. If the interface > type is AMW0_V2, why is it the right thing to do to use WMID_get_u32 if the cap > isn't ACER_CAP_MAILLED? > In commit commit 745a5d2126926808295742932d0e36d485efa485 case ACER_AMW0_V2 falls through to case ACER_WMID deliberately in function set_u32(), without reporting any error or warning. So, I thought it was fair to assume that the fall-through is intentional in both functions get_u32() and set_u32(). Otherwise I would expect to see a message indicating that interface ACER_AMW0_V2 is unavailable in function set_u32(). This is also complemented by the following... >> case ACER_WMID: >> status = WMID_get_u32(value, cap); >> break; >> @@ -1383,6 +1385,7 @@ static acpi_status set_u32(u32 value, u32 cap) >> >> return AMW0_set_u32(value, cap); >> } >> + /* fall through */ > > Similarly here. > > Are we documenting intended behavior, or covering up a bug. > Commit 5c742b45dd5fbbb6cf74d3378341704f4b23c5e8 mentions that "This was fixed in acer_acpi some time ago, but I forgot to port the patch over to acer-wmi when it was merged." Notice that this driver (acer-wmi) is based on the no-longer existing acer_acpi driver. But after googling for a while I could found the fix the original author talks about: https://repo.or.cz/acer_acpi.git/commitdiff/74c08a38875ffa9989c3100947650ac8a388c189 So, the fix is indeed similar and contains the same fall-throughs from case ACER_AMW0_V2 to case ACER_WMID in both functions get_u32() and set_u32(). Thanks -- Gustavo