oversized DMA request loop

[Joe Talbott]

I am getting an oversized DMA transfer request loop when attempting to
play a DVD with mplayer.

Mar  3 20:19:50 neptune kernel: acd0: setting up DMA failed
Mar  3 20:19:50 neptune kernel: ata1: FAILURE - oversized DMA transfer
attempt 73728 > 65536
Mar  3 20:19:50 neptune kernel: acd0: setting up DMA failed
Mar  3 20:19:50 neptune kernel: ata1: FAILURE - oversized DMA transfer
attempt 73728 > 65536

I instrumented the kernel with some kprintf()s and a panic() in an
attempt to track this down.  I've upload a coredump to
leaf:~josepht/crash/dvd_crash.tgz.  I've gone back as far as
fe667cd2edce8ea4f3dcc86526ed9759c14f0bf4 but haven't yet been able to
track down exactly when this started happening.  I was not seeing this
on a system built around Jan. 27 2011, though I'm not certain how old
the sources were prior to that build.

Here's the backtrace.  Note this panic() was manually inserted.

Unread portion of the kernel message buffer:
ata1: FAILURE - oversized DMA transfer attempt 73728 > 65536
panic: JAT: panic
cpuid = 0
Trace beginning at frame 0xda2f18c0
panic(ffffffff) at panic+0x164
panic(c05cffe9,c4747878,c0609488,12000,10000) at panic+0x164
ata_dmaload(c4747878,d2afe800,12000,2,d7110000) at ata_dmaload+0x9e
ata_begin_transaction(d9c4b788) at ata_begin_transaction+0x33b
ata_start(c4747878) at ata_start+0x1ef
ata_queue_request(d9c4b788) at ata_queue_request+0x44a
atapi_action(c4786ce8,d6a084e0,c46a4310,c49825e8,c4623f40) at
atapi_action+0x815
xpt_run_dev_sendq(c0176f2b,20,1,0,a) at xpt_run_dev_sendq+0x1a7
xpt_action(d6a084e0) at xpt_action+0x25b
cdstart(d69f25e0,d6a084e0,d6a084e0,c4623f40,1,c498261c,1) at
cdstart+0x219
xpt_run_dev_allocq(d6c38dd0,d69f25e0,c49f79d0,da2f1ae8,c0176e39) at
xpt_run_dev_allocq+0x70
xpt_schedule(d69f25e0,1) at xpt_schedule+0xec
cdstrategy(da2f1af4) at cdstrategy+0xd2
dev_dstrategy(d6b5cb10,c49f7a50) at dev_dstrategy+0xed
dsched_strategy_raw(d6c38e0c,c49f7a50,da2f1b5c,c0325612,c49b1800) at
dsched_strategy_raw+0x41
noop_queue(c49b1800,d9dda700,c49f7a50,c49b1800) at noop_queue+0x11
dsched_queue(d6c38e0c,c49f7a50) at dsched_queue+0xfe
diskstrategy(da2f1b80) at diskstrategy+0x55
dev_dstrategy(d6b5cbf0,c49f7a00,d6b5cbf0,0,0) at dev_dstrategy+0xed
physio(da2f1c00,c02fbc61,da2f1be8,c0693f38,d6b5cbf0) at physio+0x1d8
physread(da2f1be8,c0693f38,d6b5cbf0,da2f1ca0,0) at physread+0x14
dev_dread(d6b5cbf0,da2f1ca0,0,d9d0acd8,0) at dev_dread+0x6c
devfs_fo_read(d4ef2320,da2f1ca0,d4e941d8,0,d4ef2320) at
devfs_fo_read+0x150
kern_preadv(3,da2f1ca0,0,da2f1cf0,292a2800) at kern_preadv+0xfb
sys_read(da2f1cf0,1e99f,0,d6a0dee0,200282) at sys_read+0x5d
syscall2(da2f1d40) at syscall2+0x240
Xint0x80_syscall() at Xint0x80_syscall+0x36
Debugger("panic")


Here's the diff from master as of Thu Mar  3 22:33:09 EST 2011

diff --git a/sys/dev/disk/nata/ata-chipset.c b/sys/dev/disk/nata/ata-chipset.c
index 91d4444..b155bf1 100644
--- a/sys/dev/disk/nata/ata-chipset.c
+++ b/sys/dev/disk/nata/ata-chipset.c
@@ -892,6 +892,7 @@ ata_ahci_dmainit(device_t dev)
 	/* note start and stop are not used here */
 	ch->dma->setprd = ata_ahci_dmasetprd;
 	ch->dma->max_iosize = 8192 * DEV_BSIZE;
+	kprintf("JAT: %s\n", __func__);
 	if (ATA_INL(ctlr->r_res2, ATA_AHCI_CAP) & ATA_AHCI_CAP_64BIT)
 	    ch->dma->max_address = BUS_SPACE_MAXADDR;
     }
@@ -1531,6 +1532,7 @@ ata_cyrix_setmode(device_t dev, int mode)
 
     ch->dma->alignment = 16;
     ch->dma->max_iosize = 126 * DEV_BSIZE;
+	kprintf("JAT: %s\n", __func__);
 
     mode = ata_limit_mode(dev, mode, ATA_UDMA2);
 
@@ -3071,6 +3073,7 @@ ata_marvell_edma_dmainit(device_t dev)
 
 	/* chip does not reliably do 64K DMA transfers */
 	ch->dma->max_iosize = 126 * DEV_BSIZE;
+	kprintf("JAT: %s\n", __func__);
     }
 }
 
@@ -3121,6 +3124,7 @@ ata_national_setmode(device_t dev, int mode)
 
     ch->dma->alignment = 16;
     ch->dma->max_iosize = 126 * DEV_BSIZE;
+	kprintf("JAT: %s\n", __func__);
 
     mode = ata_limit_mode(dev, mode, ATA_UDMA2);
 
@@ -4454,6 +4458,7 @@ ata_serverworks_allocate(device_t dev)
     /* chip does not reliably do 64K DMA transfers */
     if (ch->dma)
 	ch->dma->max_iosize = 126 * DEV_BSIZE;
+	kprintf("JAT: %s\n", __func__);
 
     return 0;
 }
diff --git a/sys/dev/disk/nata/ata-dma.c b/sys/dev/disk/nata/ata-dma.c
index 796eec1..bc0d841 100644
--- a/sys/dev/disk/nata/ata-dma.c
+++ b/sys/dev/disk/nata/ata-dma.c
@@ -76,6 +76,7 @@ ata_dmainit(device_t dev)
     ch->dma->boundary = 128 * DEV_BSIZE;
     ch->dma->segsize = 128 * DEV_BSIZE;
     ch->dma->max_iosize = 128 * DEV_BSIZE;
+	kprintf("JAT: %s\n", __func__);
     ch->dma->max_address = BUS_SPACE_MAXADDR_32BIT;
 }
 
@@ -238,6 +239,7 @@ ata_dmaload(device_t dev, caddr_t data, int32_t count, int dir,
     if (count > ch->dma->max_iosize) {
 	device_printf(dev, "FAILURE - oversized DMA transfer attempt %d > %d\n",
 		      count, ch->dma->max_iosize);
+	panic("JAT: panic");
 	return EIO;
     }
 
diff --git a/sys/dev/disk/nata/atapi-cd.c b/sys/dev/disk/nata/atapi-cd.c
index 12926ba..f2fc2f9 100644
--- a/sys/dev/disk/nata/atapi-cd.c
+++ b/sys/dev/disk/nata/atapi-cd.c
@@ -956,8 +956,10 @@ acd_set_ioparm(device_t dev)
     struct acd_softc *cdp = device_get_ivars(dev);
     struct disk_info info;
 
-    if (ch->dma)
+    if (ch->dma) {
 	cdp->iomax = min(ch->dma->max_iosize, 65534);
+	kprintf("JAT: %s\n", __func__);
+	}
     else
 	cdp->iomax = min(DFLTPHYS, 65534);
 

Thanks,
Joe