svwsata: lost/missing interrupt

After updating two identical servers from -8 to -10, I regularily get

autoconfiguration error: svwsata0:2:0: lost interrupt
         type: ata tc_bcount: 8192 tc_skip: 0
autoconfiguration error: svwsata0:2:0: bus-master DMA error: missing interrupt, status=0x20
wd2a: DMA error writing fsbn 921744 of 921744-921759 (wd2 bn 921807; cn 914 tn 7 sn 54), xfer 38, retry 0
wd2: soft error (corrected) xfer 38

on both of them (for varying values of device, fsbn etc) on both discs. 
I didn't get them under -8.

The only relevant dmesg diff I can find wrt. an identical server still 
running -8 (though some of the discs are not 100% identical since some of them 
failed and were replaced) are

-wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133)
+wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133), NCQ (32 tags) w/PRIO

and

-wd1: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133)
-wd1(svwsata0:1:0): using PIO mode 4, Ultra-DMA mode 6 (Ultra/133) (using DMA)
+wd1: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133), WRITE DMA FUA, NCQ (32 tags)
+wd1(svwsata0:2:0): using PIO mode 4, Ultra-DMA mode 6 (Ultra/133) (using DMA), WRITE DMA FUA EXT

Any hints?