Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1714603 > unrolled thread

Re: [linux-sunxi] [PATCH 2/4] drivers: soc: sunxi: fix error processing on base address when claiming

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  Re: [linux-sunxi] [PATCH 2/4] drivers: soc: sunxi: fix error processing on base address when claiming Icenowy Zheng <icenowy@aosc.io> - 2017-08-18 08:30 +0200
    Re: [linux-sunxi] [PATCH 2/4] drivers: soc: sunxi: fix error  processing on base address when claiming Chen-Yu Tsai <wens@csie.org> - 2017-08-18 08:40 +0200

#1714603 — Re: [linux-sunxi] [PATCH 2/4] drivers: soc: sunxi: fix error processing on base address when claiming

于 2017年8月18日 GMT+08:00 下午2:21:07, Chen-Yu Tsai <wens@csie.org> 写到:
>Hi,
>
>On Wed, Aug 9, 2017 at 4:56 PM, Icenowy Zheng <icenowy@aosc.io> wrote:
>> When claiming SRAM, if the base is set to an error, it means that the
>> SRAM controller has been probed, but failed to remap the controller
>> memory zone. If the base is zero, thus the SRAM controller should be
>not
>> probed at all, and it should return -EPROBE_DEFER. However, currently
>we
>> returned -EPROBE_DEFER in the former situation, and ignored the
>latter
>> situation (which will lead to the kernel to panic).
>>
>> Fix the behavior on abnormal base address processing when claiming.
>
>Could you describe how you actually ran into this? The failure seems
>unlikely for a properly written device tree.

In fact it's possible, as the probe defering used to be broken.

On the A64 situation, the SRAM is referenced by the DE2 CCU driver, which will be probed very early -- before SRAM is probed, and the problem happens.

>
>Thanks
>ChenYu

[toc] | [next] | [standalone]

#1714609 — Re: [linux-sunxi] [PATCH 2/4] drivers: soc: sunxi: fix error processing on base address when claiming

On Fri, Aug 18, 2017 at 2:23 PM, Icenowy Zheng <icenowy@aosc.io> wrote:
>
>
> 于 2017年8月18日 GMT+08:00 下午2:21:07, Chen-Yu Tsai <wens@csie.org> 写到:
>>Hi,
>>
>>On Wed, Aug 9, 2017 at 4:56 PM, Icenowy Zheng <icenowy@aosc.io> wrote:
>>> When claiming SRAM, if the base is set to an error, it means that the
>>> SRAM controller has been probed, but failed to remap the controller
>>> memory zone. If the base is zero, thus the SRAM controller should be
>>not
>>> probed at all, and it should return -EPROBE_DEFER. However, currently
>>we
>>> returned -EPROBE_DEFER in the former situation, and ignored the
>>latter
>>> situation (which will lead to the kernel to panic).
>>>
>>> Fix the behavior on abnormal base address processing when claiming.
>>
>>Could you describe how you actually ran into this? The failure seems
>>unlikely for a properly written device tree.
>
> In fact it's possible, as the probe defering used to be broken.
>
> On the A64 situation, the SRAM is referenced by the DE2 CCU driver, which
> will be probed very early -- before SRAM is probed, and the problem happens.

OK. I see it's because the DE block's address if before almost everything
else. I was wondering why we never ran into this before.

Given there are no actual users in the kernel that could trigger this,
I'll queue this for 4.14 instead.

ChenYu

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web