steven.zhang wrote:
On Wed, 2008-05-07 at 10:36 +0200, Vladimir Pantelic wrote:
steven.zhang wrote:
> So many thanks!Vladimir.
> But why 720*480 succeeded?Its size is 2488320 byte, which exceeds 2M
> already.
> I have checked the CONSISTENT_DMA_SIZE of my arch.Its value is 14M, that
> should be enough.
yes, I saw that after sending the mail
> any other suggestion?
well, the kernel tries to find such a big contiguous piece of memory, maybe the
memory is already too fragmented at that time?
Yes, I think, we should not allocate frame buffer memory dynamic.Map a fix
memory area before kernel start?
I would do so. You are not going to free this memory ever, are you?
>
> On Wed, 2008-05-07 at 09:31 +0200, Vladimir Pantelic wrote:
>> steven.zhang wrote:
>> > Hi, all.
>> > I am porting the davincifb driver to support 1280*720 resolution.
>> > As you know, I should alloc memory for different OSD windows.
>> > To support 1280*720 p, I do it as follows:
>> >
>> > #define DISP_XRES 1280
>> > #define DISP_YRES 720
>> > #define DISP_MEMY 740
>> > #define VID0_FB_SIZE (round_32(DISP_XRES*16/8) * DISP_MEMY *
TRIPLE_BUF)
>> >
>> > using dma_alloc_coherent() to allocate 5683200byte
>> > memory.However, it fails.
>> > when define DISP_XRES be 720 and DISP_YRES be 480, it succeeds.
>> >
>> >
>> > What can be the problems? dma_alloc_coherent() can not allocate 5683200
>> > (about 5M) memory using for DMA?
>>
>> maybe this:
>>
>> http://kerneltrap.org/node/3600
>>
>> what is your CONSISTENT_DMA_SIZE, default is:
>>
>> /linux/include/asm/memory.h:
>> #define CONSISTENT_DMA_SIZE SZ_2M
>>
>> but your arch could define another value.
>>
>>
>>
>> _______________________________________________
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>> http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
>
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