> -----Original Message----- > From: Valkeinen, Tomi > Sent: Thursday, January 09, 2014 1:57 PM > To: Hiremath, Vaibhav; Ivaylo Dimitrov; Ivaylo Dimitrov > Cc: Tony Lindgren; linux-omap@xxxxxxxxxxxxxxx; linux-arm- > kernel@xxxxxxxxxxxxxxxxxxx; linux-fbdev@xxxxxxxxxxxxxxx > Subject: Re: [PATCH 1/2] ARM: omapfb: add coherent dma memory support > > On 2014-01-09 10:08, Hiremath, Vaibhav wrote: > > > No, that's what is causing issue to me. Can you try predefined address flow? > > Just to highlight, I get UNDERFLOW during boot itself, immediately when it > gets mapped to userspace. > > > > Boot LOG: > > > > > [ 4.822549] Freeing unused kernel memory: 440K (c0919000 - c0987000) > > [ 5.276615] OMAPFB: pan_display(0) > > [ 5.276625] OMAPFB: setcmap > > [ 5.276635] OMAPFB: setcmap > > [ 5.293518] OMAPFB: user mmap region start a0000000, len 1536000, off 0 > > [ 5.300171] omapdss APPLY error: FIFO UNDERFLOW on gfx, disabling the > overlay > > Hmm that's interesting... So you have some tool that's ran early, which draws > something on the screen? Or maybe that's X starting? > It's initial demo, not sure whether you heard of MATRIX demo. I am running Matrix demo As part of init script. > Ah... I think I understand now. As I mentioned, AM4x has issues already. > I think the CPU/others can block DSS when accessing memory. So, if we have > bad caching for the mapped framebuffer, the CPU will use more bandwidth > when reading/writing to it, and that will cause DSS to underflow. > Yeah, AM4x already has some issues but I am comparing normal dma_alloc and reserved Memory and I see different behavior and it could be due to bad caching for the mapped buffers. Thanks, Vaibhav -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
