[PATCH v3 1/2] content: Explain better the status clearing bits

[Eugenio PÃrez <eperezma@redhat.com>]

The spec tells that "The driver MUST NOT clear a device status bit", but
a device using PCI transport reset a virtio device writing 0 to device
status. In some way, that is to clear all its bits.

Instead of add an exception, tell explicitely the status bits that
the driver cannot clear anytime in a normal operation, so conformant
device and drivers keeps being conformant.

Signed-off-by: Eugenio PÃrez <eperezma@redhat.com>
---
 content.tex | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/content.tex b/content.tex
index 5d112af..2aa3006 100644
--- a/content.tex
+++ b/content.tex
@@ -60,9 +60,10 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev
 initialization sequence specified in
 \ref{sec:General Initialization And Device Operation / Device
 Initialization}.
-The driver MUST NOT clear a
-\field{device status} bit.  If the driver sets the FAILED bit,
-the driver MUST later reset the device before attempting to re-initialize.
+The driver MUST NOT clear ACKNOWLEDGE, DRIVER, DRIVER_OK, FEATURES_OK or
+DEVICE_NEEDS_RESET bits of \field{device status}, except if resetting the whole
+device.  If the driver sets the FAILED bit, the driver MUST later reset the
+device before attempting to re-initialize.
 
 The driver SHOULD NOT rely on completion of operations of a
 device if DEVICE_NEEDS_RESET is set.
-- 
2.27.0