Patchwork [07/17] PPC: dbdma: Allow new commands in RUN state

login
register
mail settings
Submitter Alexander Graf
Date July 1, 2013, 12:13 a.m.
Message ID <1372637622-50697-8-git-send-email-agraf@suse.de>
Download mbox | patch
Permalink /patch/255988/
State New
Headers show

Comments

Alexander Graf - July 1, 2013, 12:13 a.m.
The DBDMA controller can not change its command stream while it's
actively streaming data, true. But the fact that it's in RUN state
doesn't actually indicate anything. It could just as well be in
WAIT while in RUN. And then it's legal to change commands.

This fixes a real world issue I've encountered with Mac OS X.

Signed-off-by: Alexander Graf <agraf@suse.de>
---
 hw/misc/macio/mac_dbdma.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Patch

diff --git a/hw/misc/macio/mac_dbdma.c b/hw/misc/macio/mac_dbdma.c
index 908a123..ab32957 100644
--- a/hw/misc/macio/mac_dbdma.c
+++ b/hw/misc/macio/mac_dbdma.c
@@ -725,11 +725,11 @@  static void dbdma_write(void *opaque, hwaddr addr,
     DBDMA_DPRINTF("channel 0x%x reg 0x%x\n",
                   (uint32_t)addr >> DBDMA_CHANNEL_SHIFT, reg);
 
-    /* cmdptr cannot be modified if channel is RUN or ACTIVE */
+    /* cmdptr cannot be modified if channel is ACTIVE */
 
-    if (reg == DBDMA_CMDPTR_LO &&
-        (ch->regs[DBDMA_STATUS] & (RUN | ACTIVE)))
+    if (reg == DBDMA_CMDPTR_LO && (ch->regs[DBDMA_STATUS] & ACTIVE)) {
         return;
+    }
 
     ch->regs[reg] = value;