sata_svw: check DMA start bit before reset
commit b03e66a6be91f8389fcd902ab6c1563db1c9c06b upstream.
If kdump is triggered with pending IO, controller may not respond causing
kdump to fail.
http://marc.info/?l=linux-ide&m=133032255424658&w=2
During error recovery ata_do_dev_read_id never completes due hang
in mmio_insw.
ata_do_dev_read_id
ata_sff_data_xfer
ioread16_rep
mmio_insw
if DMA start bit is cleared before reset, PIO command is successful
and kdump succeeds.
Signed-off-by: David Milburn <dmilburn@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Cc: CAI Qian <caiqian@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 file changed