ALSA: emu8000: fix emu8000 DRAM sized 512 KiB too small
v2: Fixed result still wrong in the case of 512 KiB DRAM. Oops.
Applicable to 3.5.3 mainline.
In emu8000.c, size_dram determines the amount of memory on the sound card by
doing write/readback tests starting at 512 KiB and incrementing by 512 KiB.
On success, detected_size is updated to the successful address and testing
continues. On failure, the loop is immediately exited. The resulting
detected_size is 512 KiB too small except in two special cases:
1. If there is no memory, the initial 0 value of detected_size is used, which
is correct.
2. If the address space wraps around, detected_size is updated before the
bailout, so the result is correct.
The patch corrects all cases and was tested with an AWE64 Gold. Before:
EMU8000 [0x620]: 3584 Kb on-board memory detected
asfxload 4GMGSMT.SF2 (4174814 B) fails.
After:
EMU8000 [0x620]: 4096 Kb on-board memory detected
asfxload 4GMGSMT.SF2 succeeds.
I do not have a card with 512 KiB to test with, but by forcibly enabling the
added conditional I verified on the AWE64 Gold that it detects 512 KiB
(successfully reading from the first memory location) and does not hang the
card.
C.f. Bug 46451 https://bugzilla.kernel.org/show_bug.cgi?id=46451
Signed-off-by: David Flater <dave@flaterco.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/isa/sb/emu8000.c b/sound/isa/sb/emu8000.c
index 7188787..2aae6a0 100644
--- a/sound/isa/sb/emu8000.c
+++ b/sound/isa/sb/emu8000.c
@@ -417,9 +417,6 @@
EMU8000_SMLD_READ(emu); /* discard stale data */
if (EMU8000_SMLD_READ(emu) != UNIQUE_ID2)
break; /* no memory at this address */
-
- detected_size = size;
-
snd_emu8000_read_wait(emu);
/*
@@ -432,6 +429,18 @@
if (EMU8000_SMLD_READ(emu) != UNIQUE_ID1)
break; /* we must have wrapped around */
snd_emu8000_read_wait(emu);
+
+ /* Otherwise, it's valid memory. */
+ detected_size = size + 512 * 1024;
+ }
+
+ /* Distinguish 512 KiB from 0. */
+ if (detected_size == 0) {
+ snd_emu8000_read_wait(emu);
+ EMU8000_SMALR_WRITE(emu, EMU8000_DRAM_OFFSET);
+ EMU8000_SMLD_READ(emu); /* discard stale data */
+ if (EMU8000_SMLD_READ(emu) == UNIQUE_ID1)
+ detected_size = 512 * 1024;
}
/* wait until FULL bit in SMAxW register is false */