From mboxrd@z Thu Jan 1 00:00:00 1970 From: o@zgur.org (Ozgur) Date: Thu, 01 Feb 2018 22:27:44 +0300 Subject: clang warning: implicit conversion in intel_ddi.c:1481 In-Reply-To: <20180201180240.GA28042@kroah.com> References: <20180201180240.GA28042@kroah.com> Message-ID: <116291517513264@web58o.yandex.ru> To: kernelnewbies@lists.kernelnewbies.org List-Id: kernelnewbies.lists.kernelnewbies.org 01.02.2018, 21:03, "Greg KH" : > On Thu, Feb 01, 2018 at 06:33:30PM +0100, Ozan Alpay wrote: >> ?Dear Rodrigo Vivi, Ville Syrj?l?, >> >> ?My name is Ozan Alpay, and I am a student mentored by Lukas Bulwahn. We Hi Ozan, why did you send e-mail to kernel development e-mail list? >> ?intend to use static analysis tools on the kernel source to identify, >> ?analyze and report issues. As a very first step, we are looking into >> ?clang compiler warnings and will then move to more sophisticated tools. >> >> ?When compiling Linux 4.15 with clang, we have discovered that your commit >> ?2952cd6fb4cc ("drm/i915: Let's use more enum intel_dpll_id pll_id.") >> ?introduced the following warning: >> >> ?drivers/gpu/drm/i915/intel_ddi.c:1481:30: warning: implicit conversion from enumeration type 'enum port' to different enumeration type 'enum intel_dpll_id' [-Wenum-conversion] >> ?????????enum intel_dpll_id pll_id = port; >> >> ?To reproduce it, you can compile Linux 4.15 with clang with this command: >> >> ?make HOSTCC=clang-5.0 defconfig && make -j32 HOSTCC=clang-5.0 CC=clang-5.0 >> >> ?If you don't have clang installed in your system, you can use this simple >> ?docker setup to compile the kernel with clang: >> >> ?wget https://raw.githubusercontent.com/bulwahn/linux-kernel-analysis/master/docker/kernel-clang/Dockerfile && \ >> ?docker build -t kernel-clang . && \ >> ?docker run -v :/linux/ kernel-clang /bin/sh -c "cd linux && make CC=clang-5.0 clean && make HOSTCC=clang-5.0 defconfig && make -j32 HOSTCC=clang-5.0 CC=clang-5.0" >> >> ?While we were doing our analysis on 4.15, we noticed that you already >> ?resolved this warning on linux-next with your work in commit bb911536f07e >> ?("drm/i915: Eliminate pll->state usage from bxt_calc_pll_link()"). So, >> ?since it is resolved on linux-next and we expect that this commit will be >> ?merged in the merge window for 4.16, there is probably nothing further to >> ?do. >> >> ?Linux 4.15 is shipped with this clang warning, but we don't see the >> ?crucial need to provide a backport commit to the stable branch for 4.15. >> ?We just wanted to inform you about our analysis of this clang warning. >> ?Ultimately the final call if you would like to address this clang warning >> ?in 4.15 is yours. > > Note, I have not taken "clang warning fixes" for stable kernel updates > in the past, and I doubt I will in the future, unless the tree "builds > clean" with clang. If it eventually gets there, then yes, I will do > that. > > Note, if you are going to email this out to everyone who fixes a warning > message, you might want to reconsider it. That's going to be a lot of > work, and for people who have already fixed an issue, it's kind of > pointless to just remind them of work they have done in the past, right? > > What is the goal of these types of emails? > > thanks, > > greg k-h Ozgur