Sylwester Nawrocki <[email protected]> writes: > On 09/12/14 13:59, Krzysztof Kozlowski wrote: >> On pią, 2014-12-05 at 15:15 +0100, Krzysztof Kozlowski wrote: >>> > Audio subsystem clocks are located in separate block. On Exynos 5420 if >>> > clock for this block (from main clock domain) 'mau_epll' is gated then >>> > any read or write to audss registers will block. >>> > >>> > This kind of boot hang was observed on Arndale Octa and Peach Pi/Pit >>> > after introducing runtime PM to pl330 DMA driver. After that commit the >>> > 'mau_epll' was gated, because the "amba" clock was disabled and there >>> > were no more users of mau_epll. >>> > >>> > The system hang on one of steps: >>> > 1. Disabling unused clocks from audss block. >>> > 2. During audss GPIO setup (just before probing i2s0 because >>> > samsung_pinmux_setup() tried to access memory from audss block which >>> > was >>> > gated. >>> > >>> > Add a workaround for this by enabling the 'mau_epll' clock in probe. >>> > >>> > Signed-off-by: Krzysztof Kozlowski <[email protected]> >>> > --- >>> > drivers/clk/samsung/clk-exynos-audss.c | 29 ++++++++++++++++++++++++++++- >>> > 1 file changed, 28 insertions(+), 1 deletion(-) >> >> Sorry for pinging so quick but merge window is open and it looks like >> booting Exynos542x boards will be broken (because pl330 will no longer >> hold adma clock enabled so whole audss domain will be gated). >> >> This is a non-intrusive workaround for that issue, as wanted by >> Sylwester: >> https://lkml.org/lkml/2014/12/5/223 >> >> Any comments on this? > > The patch looks OK to me, it would be good though if someone else > has confirmed it fixes the bug. I don't have any clock patches queued > at the moment. Perhaps you could apply it directly, Mike ?
I confirm it fixes the boot hang in linux-next (next-20141210) on my exynos5800-peach-pi and exynos5420-arndale-octa. Tested both exynos_defconfig and multi_v7_defconfig. Tested-by: Kevin Hilman <[email protected]> Kevin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
