On Tue, 11 Aug 2015 16:23:39 +0300
"Michael S. Tsirkin" <> wrote:
> OK to summarize, how about:
>
> In free text:
>
> The cache mode after reset can be either writeback or writethrough.
> The actual mode can be determined by reading \field{writeback}.
>
> In conformance paragraph:
>
> The driver MUST NOT read \field{writeback} before setting
> the FEATURES_OK \field{status} bit.
>
>
> And in legacy section:
>
> Legacy drivers and drivers did not support the FEATURES_OK \field{status} bit,
> and used the device before setting the DRIVER_OK bit.
> Therefore:
>
> When using the legacy interface, the driver MAY read \field{writeback}
> before setting the FEATURES_OK \field{status} field.
But if it is using the legacy interface, it won't ever set FEATURES_OK,
no? The wording is a bit confusing.
"As the legacy interface did not support FEATURES_OK to signal end of
feature negotation, the driver MAY read \field{writeback} without the
FEATURES_OK \field{status} bit having been set."
?
Do we need to mandate that the device MUST assume the driver is operating
in legacy mode in that case?
> When using the legacy interface, the transitional devices MAY assume
> that driver features won't be changed after reading \field{writeback}.
"For a driver using the legacy interface, the transitional device MAY
assume that the driver won't change features after reading
\field{writeback}."
?
