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?
> > > > 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. > >> > >> > >> > >> _______________________________________________ > >> Davinci-linux-open-source mailing list > >> [email protected] > >> http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source > > > _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
