Re: [Linux-fbdev-devel] how to support almost compatible bo

[Petr V. <VAN...@vc...>]

On 19 Jun 01 at 16:48, Ghozlane Toumi wrote:

> -strange things : I have a value, previously stored in one bitfield R1 [7:4]
> which is now dispatched in 3 bitfields :
> { R1[24],  R1[7:4],  R2[30] }  R2 being a "new" register added to the
> architecture.
> (the value was representing a number of 64 pixel wide tiles and to maintain
> compatibility, it now reprents the number of .. 32 pixels wide tiles ...)

Do you mean that value is now (MSB to LSB) R2[30] R1[24] R1[7:4], or is
it really R2[30] R1[7:4] R1[24] ?

Anyway, easiest thing is:

if (fbinfo.capable.tile_is_64) {
   r1 = (r1 & ~0x010000F0) | ((v & 0xF) << 4) | ((v & 0x10) << (24 - 4));
   r2 = (r2 & ~0x40000000) | (v & 0x20) << (30 - 5);
} else {
   if (v > 0xF) {
      printk(KERN_DEBUG "Stupid, tile > 16!");
   }
   r1 = (r1 & ~0x000000F0) | ((v & 0xF) << 4)
}

All drivers are full of such code.
                                            Petr Vandrovec
                                            van...@vc...