On Saturday 27 November 2004 12:15, Benjamin Herrenschmidt wrote:

On Sat, 2004-11-27 at 10:56 +0800, Antonino A. Daplas wrote:

quoted

1. Lack of per-display var which prevents full restore of the console on
mode switch
2. the stty utility does not work correctly for drivers that do not have
mode validation

Ok, good.

 .../...

quoted

3.  For each correct fbset, (accepted by both driver and user), if
the timings are unique, this will be also be added to the modelist. Also,
in the unfortunate case that an illegal mode timing is accidentally
entered into the modelist, there is a mechanism to remove that entry.

Ok, though I'm not too fan of this one, I'd rather have an explicit flag
in the var passed by fbset trigger the "remember" thing... oh well,
we'll see how things goes.

You mean the mode entry deletion? That's okay, the code is minor, still
unused, and was submitted as optional, but still got merged.  It can be
easily removed.

quoted

Therefore, when doing an stty, fbcon will only look at info->modelist,
finds the best matching mode, builds a var from that particular entry
and passes the var to the driver.  There is no guesswork involved, and
drivers will always operate on known working mode timings.

Yah, I know that problem, this looks like a good solution.

quoted

Also, the graphics states per console are also preserved.  However,
instead of saving a var per console, we only save a part of the var, the
graphics state. The mode timings are saved as pointers to entries in
info->modelist. In effect, we have the full functionality of a
per-display var, but we save half the memory, that's around 5K.

I dislike the pointers tho. Remember that one day, we'll do monitor
hotswap, which means that at one point, the driver will
remove/add/rebuild modelist...

Removing/adding/rebuilding the modelist should be doable with pointers. But
in the case people don't want pointers, this can be easily changed.  The
conversion code is entirely in display_to_var() and var_to_display() helpers.
  
Tony




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