From mboxrd@z Thu Jan 1 00:00:00 1970 From: sylvester.nawrocki@gmail.com (Sylwester Nawrocki) Date: Sat, 27 Jul 2013 00:04:30 +0200 Subject: [PATCH v2] clk: exynos4: Add CLK_GET_RATE_NOCACHE flag for the Exynos4x12 ISP clocks In-Reply-To: <20130726203026.7598.21711@quantum> References: <1374786425-6697-1-git-send-email-sylvester.nawrocki@gmail.com> <20130726203026.7598.21711@quantum> Message-ID: <51F2F26E.4090909@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 07/26/2013 10:30 PM, Mike Turquette wrote: > Quoting Sylwester Nawrocki (2013-07-25 14:07:05) >> From: Sylwester Nawrocki >> >> The ISP clock registers belong to the ISP power domain and may change >> their values if this power domain is switched off/on. Add >> CLK_GET_RATE_NOCACHE flags to ensure we do not rely on invalid cached >> data when setting or getting frequency of those clocks. >> >> Signed-off-by: Sylwester Nawrocki >> Signed-off-by: Kyungmin Park > > Thanks for the fix. I've taken into clk-fixes. Is there a specific > regression this fixes (besides just having wrong clock rates). I can > amend the changelog if you have an example (e.g. device X explodes). Hmm, yes, this fixes a pretty serious problem. There is a companion commit [1] already in Linus' tree, more details can be found there. Perhaps something like this could be added: "Otherwise the FIMC-IS Cortex-A5 core and AXI bus clocks have incorrect frequencies, which breaks the ISP operation and starting the video pipeline fails with timeouts reported by the FIMC-IS firmware. See related commit 722a860ecb29aa34ec6f7d7f32b949209e8 "[media] exynos4-is: Fix FIMC-IS clocks initialization" for more details." [1] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit?id=722a860ecb29aa34ec6f7d7f32b949209e86a2f3 Thanks, Sylwester