Hi Javier,
On 2017-01-18 01:30, Javier Martinez Canillas wrote:
Commit 15f90ab57acc ("[media] exynos-gsc: Make driver functional when
CONFIG_PM is unset") removed the implicit dependency that the driver
had with CONFIG_PM, since it relied on the config option to be enabled.
In order to work with !CONFIG_PM, the GSC reset logic that happens in
the runtime resume callback had to be executed on the probe function.
The problem is that if CONFIG_PM is enabled, the power domain for the
GSC could be disabled and so an attempt to write to the GSC_SW_RESET
register leads to an unhandled fault / imprecise external abort error:
Driver core ensures that driver's probe() is called with respective power
domain turned on, so this is not the right reason for the proposed change.
[ 10.178825] Unhandled fault: imprecise external abort (0x1406) at 0x00000000
[ 10.186982] pgd = ed728000
[ 10.190847] [00000000] *pgd=00000000
[ 10.195553] Internal error: : 1406 [#1] PREEMPT SMP ARM
[ 10.229761] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[ 10.237134] task: ed49e400 task.stack: ed724000
[ 10.242934] PC is at gsc_wait_reset+0x5c/0x6c [exynos_gsc]
[ 10.249710] LR is at gsc_probe+0x300/0x33c [exynos_gsc]
[ 10.256139] pc : [<bf2429e0>] lr : [<bf240734>] psr: 60070013
[ 10.256139] sp : ed725d30 ip : 00000000 fp : 00000001
[ 10.271492] r10: eea74800 r9 : ecd6a2c0 r8 : ed7d8854
[ 10.277912] r7 : ed7d8c08 r6 : ed7d8810 r5 : ffff8ecd r4 : c0c03900
[ 10.285664] r3 : 00000000 r2 : 00000001 r1 : ed7d8b98 r0 : ed7d8810
So only do a GSC reset if CONFIG_PM is disabled, since if is enabled the
runtime PM resume callback will be called by the VIDIOC_STREAMON ioctl,
making the reset in probe unneeded.
Fixes: 15f90ab57acc ("[media] exynos-gsc: Make driver functional when CONFIG_PM is unset")
Signed-off-by: Javier Martinez Canillas <javier@xxxxxxxxxxxxxxx>
Frankly, I don't get why this change is needed.
---
I-ve only tested with CONFIG_PM enabled since my Exynos5422 Odroid
XU4 board fails to boot when the config option is disabled.
Best regards,
Javier
drivers/media/platform/exynos-gsc/gsc-core.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/media/platform/exynos-gsc/gsc-core.c b/drivers/media/platform/exynos-gsc/gsc-core.c
index 83272f10722d..42e1e09ea915 100644
--- a/drivers/media/platform/exynos-gsc/gsc-core.c
+++ b/drivers/media/platform/exynos-gsc/gsc-core.c
@@ -1083,8 +1083,10 @@ static int gsc_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, gsc);
- gsc_hw_set_sw_reset(gsc);
- gsc_wait_reset(gsc);
+ if (!IS_ENABLED(CONFIG_PM)) {
+ gsc_hw_set_sw_reset(gsc);
+ gsc_wait_reset(gsc);
+ }
vb2_dma_contig_set_max_seg_size(dev, DMA_BIT_MASK(32));
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
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