Messages in this thread |  | | Subject | Re: [PATCH 6/6] ARM: da850: adjust memory settings for tilcdc | From | Peter Ujfalusi <> | Date | Wed, 5 Oct 2016 11:02:36 +0300 |
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On 10/04/16 12:20, Bartosz Golaszewski wrote: > 2016-09-30 21:19 GMT+02:00 Peter Ujfalusi <peter.ujfalusi@ti.com>: >> On 09/30/2016 06:06 PM, Bartosz Golaszewski wrote: >>> >>> Just ran a quick test with speaker-test -c2 -twav. Besides the fact >>> that the left and right channels are inverted (I'm looking into that), >>> I didn't notice any problems. Even at 1024x768 resolution, playing >>> audio at the same time seems to work fine. >> > > Hi Peter > >> That's good to hear, but I think the priorities should be set: >> LCDC and EDMA30TC1 to highest priority >> EDMA30TC0 to priority 2 >> >> The 0TC0 is used by MMC and if you want to play a video you might need the >> servicing TC to be higher priority then other masters. >> >> If audio playback would trigger sync losts in lcdc then we might need to move >> 0TC1 to priority 1. >> > > Did you mean "set EDMA31TC0 to priority 2"? EDMA30TC0 is already at > the highest priority. Or did you mean that we need to lower the > EDMA30TC0 priority? In that case: is 2 the correct value? EDMA31TC0 is > used by mmc1 and its priority is 4. Shouldn't we set both to be the > same?
What I mean is: EMDA30TC1 = LCDC = 0; EDMA30TC0 = 2;
I don't know what the MMC1 is used on the LCDK, but it is only used by add-on card on Logic's OMAP-L138 EVM (wifi if I recall right). I would leave EDMA31TC0 as 4.
And while we are here: this is my problem, I don't want LCDC to be high priority on OMAP-L138 EVM as it has no display by default, no point of fiddling with the EMIF priority there.
This is the reason why we should have a way via DT to set these priorities. A DT fragment for OMAP-L138 EVM's wifi module might want to increase the EDMA31TC0 priority to get better throughput, but on a bare board we don't want that. If I would have the display module for the EVM, I would like to rise the LCDC priority also, but I don't have one. If I have the aduio add-on module I would want to keep audio as the highest priority (and the MMC0 to be able to record/play audio files). etc.
>> I agree that LCDC priority needs to be higher, but I do wonder why the default >> (5) is not working and if it is not working why it is 5... >> >> My guess is that the change in the PBBPR register is the one actually helping >> here. >> > > While it seems that lowering the EDMA30TC0 priority is indeed > unnecessary, if I don't set the LCDC master to priority 0, I still get > FIFO underflows even with the change in PBBPR.
I believe it is valid to raise the LCDC priority, but I wonder what blocks the LCDC accesses when you don't really have anything going on in the background.
-- Péter
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