DVDInterface: Don't evict cache block i unless block i + 2 was read #9847
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As was mentioned on IRC, while not a "complete" test, my early results seem to show that timing is on par with GameCube, and maybe ever so slightly slower than Wii. This also fixes Pitfall: The Big Adventure (Wii port), which had the exact same issue. I can't really tell exact timing differences, because I don't have enough data. But as far as I, and the rest of the Pitfall Speed running community, is concerned, this looks good and pretty close to console. Timing comparisons as compiled by our community: https://docs.google.com/spreadsheets/d/16kTAM4g4qUmREwehROz_tzjOS3DXJHLGa44FKWy7GNI/edit#gid=0 |
| // Update the buffer based on this read. Based on hardware testing, the blocks which are kept are | ||
| // the most recently accessed block, the block immediately before it, and all blocks after it. | ||
| // If the block immediately before the most recently accessed block is not kept, we get too long | ||
| // loading screens in Pitfall: The Lost Expedition (https://bugs.dolphin-emu.org/issues/1227). |
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This link is wrong; it should be https://bugs.dolphin-emu.org/issues/12279 (it's missing the 9).
Also, "we get too long loading screens" sounds a bit awkward to me; maybe "loading takes longer than it should" would be better?
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I've updated the comment.
Intends to fix https://bugs.dolphin-emu.org/issues/12279. I have hardware tested the behavior, but I haven't tested the game.
If we seek to a block that isn't in the cache, the block prior to it doesn't end up getting read into the buffer.
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Code looks good to me.
It might be useful to implement DICommand::Seek at some point, but it doesn't seem to be used by many games in my experience. As far as I know, it essentially acts as a read except it doesn't perform the DMA afterwards. Unfortunately I'm not sure where I read that. But it's not something that needs to be done for this PR.
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I retested again to make sure everything looked fine. I'm assuming this won't cause any regressions, but who knows. |
Intends to fix https://bugs.dolphin-emu.org/issues/12279. I have hardware tested the behavior, but I haven't tested the game.