From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51526) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YDbax-0001pO-LH for qemu-devel@nongnu.org; Tue, 20 Jan 2015 11:24:00 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YDbas-0002a0-St for qemu-devel@nongnu.org; Tue, 20 Jan 2015 11:23:59 -0500 From: Paolo Bonzini Date: Tue, 20 Jan 2015 17:23:48 +0100 Message-Id: <1421771028-5251-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH] sb16: fix interrupt acknowledgement List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: j_bair@bellsouth.net, Gerd Hoffmann , qemu-stable@nongnu.org SoundBlaster 16 emulation is very broken and consumes a lot of CPU, but a small fix was suggested offlist and it is enough to fix some games. I got Epic Pinball to work with the "SoundBlaster Clone" option. The processing of the interrupt register is wrong due to two missing "not"s. This causes the interrupt flag to remain set even after the Acknowledge ports have been read (0x0e and 0x0f). The line was introduced by commit 85571bc (audio merge (malc), 2004-11-07), but the code might have been broken before because I did not look closely at the huge patches from 10 years ago. Reported-by: Joshua Bair Cc: Gerd Hoffmann Cc: qemu-stable@nongnu.org Signed-off-by: Paolo Bonzini --- hw/audio/sb16.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/hw/audio/sb16.c b/hw/audio/sb16.c index bda26d0..444eb9e 100644 --- a/hw/audio/sb16.c +++ b/hw/audio/sb16.c @@ -999,7 +999,7 @@ static IO_READ_PROTO (dsp_read) retval = (!s->out_data_len || s->highspeed) ? 0 : 0x80; if (s->mixer_regs[0x82] & 1) { ack = 1; - s->mixer_regs[0x82] &= 1; + s->mixer_regs[0x82] &= ~1; qemu_irq_lower (s->pic); } break; @@ -1008,7 +1008,7 @@ static IO_READ_PROTO (dsp_read) retval = 0xff; if (s->mixer_regs[0x82] & 2) { ack = 1; - s->mixer_regs[0x82] &= 2; + s->mixer_regs[0x82] &= ~2; qemu_irq_lower (s->pic); } break; -- 2.1.0