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IPU DMA: If no underflow occurs on QWC = 0, end DMA. 

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This commit is contained in:
refractionpcsx2 2022-01-22 20:01:15 +00:00
parent 398f675412
commit 7b6db5ad7a
1 changed files with 13 additions and 0 deletions
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13
pcsx2/IPU/IPUdma.cpp
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@ -197,6 +197,19 @@ __fi void dmaIPU0() // fromIPU
//IPU_INT_FROM( 160 );
// Update 22/12/2021 - Doesn't seem to need this now after fixing some FIFO/DMA behaviour
IPU0dma();
// Explanation of this:
// The DMA logic on a NORMAL transfer is generally a "transfer first, ask questions later" so when it's sent
// QWC == 0 (which we change to 0x10000) it transfers, causing an underflow, then asks if it's reached 0
// since IPU_FROM is beholden to the OUT FIFO, if there's nothing to transfer, it will stay at 0 and won't underflow
// so the DMA will end.
if (ipu0ch.qwc == 0x10000)
{
ipu0ch.qwc = 0;
ipu0ch.chcr.STR = false;
hwDmacIrq(DMAC_FROM_IPU);
DMA_LOG("IPU0 DMA End");
}
}
__fi void dmaIPU1() // toIPU