revert VidHD passive mode detection

res/history.md

@@ -21,11 +21,10 @@
  - Removed latent copy protection in Sea Dragon (sneaky sneaky)
  - Enable fast machine speed or accelerator (if available) to speed up searching, browsing, and game launching
  - Prevent flashes of other game screenshots while loading a demo or game
- - Detect VidHD in passive mode
  - Fixed a freeze on startup with certain accelerators
  - Fixed a crash on Apple ][+
  - Fixed choppy sound in some games on Apple IIgs
- - Fixed launching from MicroDrive partition 3+
+ - Fixed launching from MicroDrive partition 3+ (in progress)
  - Fixed launching from CFFA 3000 partition 5+
  - Fixed launching from RamFAST "GS/OS partitions"
  - Fixed launching from ProDOS 2.5

src/hw.vidhd.a

@@ -33,39 +33,6 @@ HasVidHDCard
          dex
          cpx   #$C0
          bne   @slotLoop
-
-         ; check for a slot where the Cx00 page is all zeroes
-         ; and the devsel bytes are also all zeroes, which
-         ; indicates that VidHD is probably present but is in
-         ; passive mode because some other card is hogging DMA
-         ldx   #$C7
-@passiveSlotLoop
-         stx   @passiveByteLoop+2
-         ldy   #0
-@passiveByteLoop
-         lda   $FD00, y              ; SMC (high byte)
-         bne   @passiveNextSlot
-         dey
-         bne   @passiveByteLoop
-         txa
-         and   #$0F                  ; A = $01..$07
-         asl
-         asl
-         asl
-         asl                         ; A = $10..$70
-         ora   #$80                  ; A = $90..$F0
-         sta   @devselLoop+1
-         ldy   #$0F
-@devselLoop
-         lda   $C0FD, y              ; SMC (low byte)
-         bne   @passiveNextSlot
-         dey
-         bpl   @devselLoop
-         bmi   @found                ; always branches
-@passiveNextSlot
-         dex
-         cpx   #$C0
-         bne   @passiveSlotLoop
          clc                         ; not found
          rts
 @kVidHDMagicBytes