Winter Sports 2009 The Next Challenge (E) - Glitched graphic on both screen

[DarkSwan86]

As you can see from the screenshot, on the top screen there is a line that corrupt the image on the background. Sometimes the same line corrupt the bottom screen. This problem affect both render.

--- ROM INFO ---
ROM game code: CWSP
ROM serial: NTR-CWSP-EUR
ROM chipID: 00001FC2
ROM internal name: WINTERSPORTS
ROM developer: Unknown

--- PC INFO ---
CPU: Intel i5-4670K
GPU: AMD Radeon 7950
Driver version: Crimson ReLive Edition 16.12.2 (December 2016)
OS: Windows 7 x64

[zeromus]

This game is 'pacing the beam' with a dma triggered at scanline 90 meant to refill 96 scanlines worth of BG data. By the time the LCD gets to scanline 96, the DMA should not have overwritten the final 6 scanlines of the top half. However, we emulate the DMA instantaneously, and so those scanlines are displayed with the data intended for the bottom half.

This can't be fixed properly without a major rewrite of the DMA engine which will have a considerable impact on performance.

[DarkSwan86]

Same problem with 44ac04d