| Message ID | 20190319132601.3589-1-m.szyprowski@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ARM: dts: exynos: Increase minimal ACLK400_DISP1 frequency on Exynos542x | expand |
On Tue, Mar 19, 2019 at 02:26:01PM +0100, Marek Szyprowski wrote: > ACLK400_DISP1 bus feeds some internal buses of the display subsystem, some > of which are also related to TV/Mixer hardware modules. When that bus > is set to 120MHz, Exynos Mixer is not able to properly handle two XRGB > display planes at FullHD-60MHz. DMA underrun happens, which in turn might > result in reading data out of the configured buffer, what causes IOMMU > page fault and kernel panic. > > This change fixes the following IOMMU fault, observed, when 2 Mixer planes > were enabled: > > exynos-sysmmu 14650000.sysmmu: 14450000.mixer: PAGE FAULT occurred at 0x20fe9000 > ------------[ cut here ]------------ > kernel BUG at ../drivers/iommu/exynos-iommu.c:450! > Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM > Modules linked in: > CPU: 5 PID: 0 Comm: swapper/5 Not tainted 5.0.0-00003-g1b03088168ea #149 > Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) > PC is at exynos_sysmmu_irq+0x1c0/0x264 > LR is at lock_is_held_type+0x44/0x64 > ... > > Reported-by: Marian Mihailescu <mihailescu2m@gmail.com> > Fixes: 5d99cc59a3c6 ("ARM: dts: exynos: Move Exynos5250 and Exynos5420 nodes under soc") > Fixes: b04a62d3ade3 ("ARM: dts: exynos: Add bus nodes using VDD_INT for Exynos542x SoC") > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> > --- > arch/arm/boot/dts/exynos5420.dtsi | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm/boot/dts/exynos5420.dtsi b/arch/arm/boot/dts/exynos5420.dtsi > index aaff15880761..250f4d7182e0 100644 > --- a/arch/arm/boot/dts/exynos5420.dtsi > +++ b/arch/arm/boot/dts/exynos5420.dtsi > @@ -1294,7 +1294,7 @@ > compatible = "operating-points-v2"; > > opp00 { > - opp-hz = /bits/ 64 <120000000>; > + opp-hz = /bits/ 64 <150000000>; Some time ago we talked about all these changes on IRC. I understand that implementing proper QoS (or fix devfreq/PPMU events to properly indicate busy mixer) might be a big task so let's go with this workaround. However how about adding a TODO comment about reason of bumping the frequency? Best regards, Krzysztof
diff --git a/arch/arm/boot/dts/exynos5420.dtsi b/arch/arm/boot/dts/exynos5420.dtsi index aaff15880761..250f4d7182e0 100644 --- a/arch/arm/boot/dts/exynos5420.dtsi +++ b/arch/arm/boot/dts/exynos5420.dtsi @@ -1294,7 +1294,7 @@ compatible = "operating-points-v2"; opp00 { - opp-hz = /bits/ 64 <120000000>; + opp-hz = /bits/ 64 <150000000>; }; opp01 { opp-hz = /bits/ 64 <200000000>;
ACLK400_DISP1 bus feeds some internal buses of the display subsystem, some of which are also related to TV/Mixer hardware modules. When that bus is set to 120MHz, Exynos Mixer is not able to properly handle two XRGB display planes at FullHD-60MHz. DMA underrun happens, which in turn might result in reading data out of the configured buffer, what causes IOMMU page fault and kernel panic. This change fixes the following IOMMU fault, observed, when 2 Mixer planes were enabled: exynos-sysmmu 14650000.sysmmu: 14450000.mixer: PAGE FAULT occurred at 0x20fe9000 ------------[ cut here ]------------ kernel BUG at ../drivers/iommu/exynos-iommu.c:450! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM Modules linked in: CPU: 5 PID: 0 Comm: swapper/5 Not tainted 5.0.0-00003-g1b03088168ea #149 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) PC is at exynos_sysmmu_irq+0x1c0/0x264 LR is at lock_is_held_type+0x44/0x64 ... Reported-by: Marian Mihailescu <mihailescu2m@gmail.com> Fixes: 5d99cc59a3c6 ("ARM: dts: exynos: Move Exynos5250 and Exynos5420 nodes under soc") Fixes: b04a62d3ade3 ("ARM: dts: exynos: Add bus nodes using VDD_INT for Exynos542x SoC") Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> --- arch/arm/boot/dts/exynos5420.dtsi | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)