From: "Andrew F. Davis" <afd@ti.com>
To: Ayan Halder <Ayan.Halder@arm.com>, John Stultz <john.stultz@linaro.org>
Cc: Brian Starkey <Brian.Starkey@arm.com>, nd <nd@arm.com>,
Sudipto Paul <Sudipto.Paul@arm.com>,
Vincent Donnefort <Vincent.Donnefort@arm.com>,
Chenbo Feng <fengc@google.com>,
Alistair Strachan <astrachan@google.com>,
Liam Mark <lmark@codeaurora.org>,
lkml <linux-kernel@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>,
DRI mailing list <dri-devel@lists.freedesktop.org>,
Hridya Valsaraju <hridya@google.com>,
Pratik Patel <pratikp@codeaurora.org>
Subject: Re: [RESEND][PATCH v8 0/5] DMA-BUF Heaps (destaging ION)
Date: Sat, 19 Oct 2019 09:41:27 -0400 [thread overview]
Message-ID: <2c60496c-d536-05e7-bbf6-ca718b8142bd@ti.com> (raw)
In-Reply-To: <20191018185723.GA27993@arm.com>
On 10/18/19 2:57 PM, Ayan Halder wrote:
> On Fri, Oct 18, 2019 at 11:49:22AM -0700, John Stultz wrote:
>> On Fri, Oct 18, 2019 at 11:41 AM Ayan Halder <Ayan.Halder@arm.com> wrote:
>>> On Fri, Oct 18, 2019 at 09:55:17AM +0000, Brian Starkey wrote:
>>>> On Thu, Oct 17, 2019 at 01:57:45PM -0700, John Stultz wrote:
>>>>> On Thu, Oct 17, 2019 at 12:29 PM Andrew F. Davis <afd@ti.com> wrote:
>>>>>> On 10/17/19 3:14 PM, John Stultz wrote:
>>>>>>> But if the objection stands, do you have a proposal for an alternative
>>>>>>> way to enumerate a subset of CMA heaps?
>>>>>>>
>>>>>> When in staging ION had to reach into the CMA framework as the other
>>>>>> direction would not be allowed, so cma_for_each_area() was added. If
>>>>>> DMA-BUF heaps is not in staging then we can do the opposite, and have
>>>>>> the CMA framework register heaps itself using our framework. That way
>>>>>> the CMA system could decide what areas to export or not (maybe based on
>>>>>> a DT property or similar).
>>>>>
>>>>> Ok. Though the CMA core doesn't have much sense of DT details either,
>>>>> so it would probably have to be done in the reserved_mem logic, which
>>>>> doesn't feel right to me.
>>>>>
>>>>> I'd probably guess we should have some sort of dt binding to describe
>>>>> a dmabuf cma heap and from that node link to a CMA node via a
>>>>> memory-region phandle. Along with maybe the default heap as well? Not
>>>>> eager to get into another binding review cycle, and I'm not sure what
>>>>> non-DT systems will do yet, but I'll take a shot at it and iterate.
>>>>>
>>>>>> The end result is the same so we can make this change later (it has to
>>>>>> come after DMA-BUF heaps is in anyway).
>>>>>
>>>>> Well, I'm hesitant to merge code that exposes all the CMA heaps and
>>>>> then add patches that becomes more selective, should anyone depend on
>>>>> the initial behavior. :/
>>>>
>>>> How about only auto-adding the system default CMA region (cma->name ==
>>>> "reserved")?
>>>>
>>>> And/or the CMA auto-add could be behind a config option? It seems a
>>>> shame to further delay this, and the CMA heap itself really is useful.
>>>>
>>> A bit of a detour, comming back to the issue why the following node
>>> was not getting detected by the dma-buf heaps framework.
>>>
>>> reserved-memory {
>>> #address-cells = <2>;
>>> #size-cells = <2>;
>>> ranges;
>>>
>>> display_reserved: framebuffer@60000000 {
>>> compatible = "shared-dma-pool";
>>> linux,cma-default;
>>> reusable; <<<<<<<<<<<<-----------This was missing in our
>>> earlier node
>>> reg = <0 0x60000000 0 0x08000000>;
>>> };
>>
>> Right. It has to be a CMA region for us to expose it from the cma heap.
>>
>>
>>> With 'reusable', rmem_cma_setup() succeeds , but the kernel crashes as follows :-
>>>
>>> [ 0.450562] WARNING: CPU: 2 PID: 1 at mm/cma.c:110 cma_init_reserved_areas+0xec/0x22c
>>
>> Is the value 0x60000000 you're using something you just guessed at? It
>> seems like the warning here is saying the pfn calculated from the base
>> address isn't valid.
> It is a valid memory region we use to allocate framebuffers.
But does it have a valid kernel virtual mapping? Most ARM systems (just
assuming you are working on ARM :)) that I'm familiar with have the DRAM
space starting at 0x80000000 and so don't start having valid pfns until
that point. Is this address you are reserving an SRAM?
Andrew
>>
>> thanks
>> -john
next prev parent reply other threads:[~2019-10-19 13:42 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-06 18:47 [RESEND][PATCH v8 0/5] DMA-BUF Heaps (destaging ION) John Stultz
2019-09-06 18:47 ` [RESEND][PATCH v8 1/5] dma-buf: Add dma-buf heaps framework John Stultz
2019-09-23 22:08 ` Brian Starkey
2019-09-24 17:10 ` John Stultz
2019-09-06 18:47 ` [RESEND][PATCH v8 2/5] dma-buf: heaps: Add heap helpers John Stultz
2019-09-23 22:08 ` Brian Starkey
2019-09-06 18:47 ` [RESEND][PATCH v8 3/5] dma-buf: heaps: Add system heap to dmabuf heaps John Stultz
2019-09-23 22:09 ` Brian Starkey
2019-09-06 18:47 ` [RESEND][PATCH v8 4/5] dma-buf: heaps: Add CMA " John Stultz
2019-09-23 22:10 ` Brian Starkey
2019-09-06 18:47 ` [RESEND][PATCH v8 5/5] kselftests: Add dma-heap test John Stultz
2019-09-23 22:11 ` Brian Starkey
2019-09-26 21:36 ` John Stultz
2019-09-27 9:20 ` Brian Starkey
2019-09-19 16:51 ` [RESEND][PATCH v8 0/5] DMA-BUF Heaps (destaging ION) Sumit Semwal
2019-09-24 16:22 ` Ayan Halder
2019-09-24 16:28 ` John Stultz
2019-10-09 17:37 ` Ayan Halder
2019-10-09 18:27 ` Andrew F. Davis
2019-10-14 9:07 ` Brian Starkey
2019-10-16 17:40 ` Andrew F. Davis
2019-10-17 19:14 ` John Stultz
2019-10-17 19:29 ` Andrew F. Davis
2019-10-17 20:57 ` John Stultz
2019-10-18 9:55 ` Brian Starkey
2019-10-18 18:33 ` John Stultz
2019-10-18 18:41 ` Ayan Halder
2019-10-18 18:49 ` John Stultz
2019-10-18 18:57 ` Ayan Halder
2019-10-18 19:04 ` John Stultz
2019-10-19 13:41 ` Andrew F. Davis [this message]
2019-10-21 9:18 ` Brian Starkey
2019-10-22 13:51 ` Ayan Halder
2019-10-18 18:51 ` Ayan Halder
2019-10-16 17:34 ` John Stultz
2019-09-30 13:40 ` Laura Abbott
[not found] ` <20190930074335.6636-1-hdanton@sina.com>
2019-10-01 20:50 ` [RESEND][PATCH v8 3/5] dma-buf: heaps: Add system heap to dmabuf heaps John Stultz
[not found] ` <20190930032651.8264-1-hdanton@sina.com>
2019-10-02 16:14 ` [RESEND][PATCH v8 1/5] dma-buf: Add dma-buf heaps framework John Stultz
[not found] ` <20190930081434.248-1-hdanton@sina.com>
2019-10-02 16:15 ` [RESEND][PATCH v8 4/5] dma-buf: heaps: Add CMA heap to dmabuf heaps John Stultz
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