[PATCH v3 1/4] ARM: pxa: add memory resource to RTC device
robert.jarzmik at free.fr
Tue May 12 13:24:49 PDT 2015
Robert Jarzmik <robert.jarzmik at free.fr> writes:
> Rob Herring <robh at kernel.org> writes:
>>> This really isn't a good idea - what do you think happens when
>>> the same struct resource gets passed into insert_resource()
>> Bad things. If you recall, we discussed this on v1. See the commit
>> msg of patch 2 for the summary. There is not currently a problem
>> because the rtc-pxa driver does not request the resource.
> I think you're talking about resource claiming, while Russell is talking about
> resource declaration.
> The point Russell is raising is if you do a platform_add_device() twice with the
> same resource (which is done in pxa, once for sa1100-rtc, once for pxa-rtc), you
> call insert_resource() twice with the same resource structure.
> I had not thought of that before (that's in my reply noted "nasty consequences"
> in ), and I'll do my homework this week, and try this only patch, but if I
> follow Russell's thinking, then sa1100-rtc and pxa-rtc cannot be declared
> together anymore.
I made the try, and Russell was right, this breaks the pxa architecture. The
relevant extract of kernel message is in .
The consequences with your patches :
- the pxa_device_rtc fails (as resource is duplicated)
- all the devices are unregistered (rollback)
And pxa27x fails.
Now I'm pondering about the right approach :
- either remove sa1100_device_rtc from pxas
- or remove pxa_device_rtc
- or both
- or something else
Let me think a bit about it.
2015/05/12 22:12:57 ------------[ cut here ]------------
2015/05/12 22:12:57 WARNING: CPU: 0 PID: 1 at kernel/resource.c:755 __insert_resource+0x74/0x134()
2015/05/12 22:12:57 Modules linked in:
2015/05/12 22:12:57 CPU: 0 PID: 1 Comm: swapper Tainted: G W 4.0.0-00004-g7fa5ed0 #528
2015/05/12 22:12:57 Hardware name: Intel HCDDBBVA0 Development Platform (aka Mainstone)
2015/05/12 22:12:57 [<c000e170>] (unwind_backtrace) from [<c000c064>] (show_stack+0x10/0x14)
2015/05/12 22:12:57 [<c000c064>] (show_stack) from [<c00176b0>] (warn_slowpath_common+0x7c/0xb4)
2015/05/12 22:12:57 [<c00176b0>] (warn_slowpath_common) from [<c0017784>] (warn_slowpath_null+0x1c/0x24)
2015/05/12 22:12:57 [<c0017784>] (warn_slowpath_null) from [<c001ada4>] (__insert_resource+0x74/0x134)
2015/05/12 22:12:57 [<c001ada4>] (__insert_resource) from [<c001bfd4>] (insert_resource_conflict+0x20/0x60)
2015/05/12 22:12:57 [<c001bfd4>] (insert_resource_conflict) from [<c001c01c>] (insert_resource+0x8/0x18)
2015/05/12 22:12:57 [<c001c01c>] (insert_resource) from [<c0207a7c>] (platform_device_add+0x88/0x254)
2015/05/12 22:12:57 [<c0207a7c>] (platform_device_add) from [<c02082c4>] (platform_add_devices+0x34/0x70)
2015/05/12 22:12:57 [<c02082c4>] (platform_add_devices) from [<c00088e0>] (do_one_initcall+0xa8/0x204)
2015/05/12 22:12:58 [<c00088e0>] (do_one_initcall) from [<c050dd6c>] (kernel_init_freeable+0xf4/0x1b4)
2015/05/12 22:12:58 [<c050dd6c>] (kernel_init_freeable) from [<c03b5a9c>] (kernel_init+0x8/0xec)
2015/05/12 22:12:58 [<c03b5a9c>] (kernel_init) from [<c0009698>] (ret_from_fork+0x14/0x3c)
2015/05/12 22:12:58 ---[ end trace cb88537fdc8fa201 ]---
2015/05/12 22:12:58 platform pxa-rtc: failed to claim resource 0
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