Timothy Normand Miller wrote:
Something we need to be able to do is enable the interrupt for video.
Generally, we only need one interrupt per frame, so what we need to do
is set the interrupt bit in one of the instructions at the end of the
last active scanline. The thing is, it's not adequate to make that a
parameter to the programming function... we need to turn the interrupt
on and off quite a lot, so what would be nice is to have another
function to call that enables/disabled interrupts by rewriting the
right instruction with the flag changed. The problem is that we need
to somehow keep track of which instruction this is, for multiple cards
with more than one video head each.
Perhaps it would just be simpler to always set the interrupt in the
right instruction and have a mask bit in the global config registers.
Perhaps it would be even simpler to have two interrupts. One as you
describe -- a sync interrupt -- which could not be turned off, A second
for a service request which would be triggered by firmware on the board
or the DMA controller.
Then the issue of turning the sync interrupt off and on is moved to the
driver since the APIC Intel acronym == Advanced Programmable Interrupt
Controller) on the motherboard already has the hardware to turn off
(ignore) an interrupt.
--
JRT
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