[PATCH] drm/mgag200: Hardware cursor support
Dave Airlie
airlied at gmail.com
Mon Jun 17 02:32:25 PDT 2013
On Thu, Jun 13, 2013 at 3:17 AM, Christopher Harvey <charvey at matrox.com> wrote:
> On Wed, Jun 05 2013, Christopher Harvey <charvey at matrox.com> wrote:
>> G200 cards support, at best, 16 colour palleted images for the cursor
>> so we do a conversion in the cursor_set function, and reject cursors
>> with more than 16 colours, or cursors with partial transparency. Xorg
>> falls back gracefully to software cursors in this case.
>>
>> We can't disable/enable the cursor hardware without causing momentary
>> corruption around the cursor. Instead, once the cursor is on we leave
>> it on, and simulate turning the cursor off by moving it
>> offscreen. This works well.
>>
>> Since we can't disable -> update -> enable the cursors, we double
>> buffer cursor icons, then just move the base address that points to
>> the old cursor, to the new. This also works well, but uses an extra
>> page of memory.
>>
>> The cursor buffers are lazily-allocated on first cursor_set. This is
>> to make sure they don't take priority over any framebuffers in case of
>> limited memory.
>>
>> Here is a representation of how the bitmap for the cursor is mapped in G200 memory :
>>
>> Each line of color cursor use 6 Slices of 8 bytes. Slices 0 to 3
>> are used for the 4bpp bitmap, slice 4 for XOR mask and slice 5 for
>> AND mask. Each line has the following format:
>>
>> // Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7
>> //
>> // S0: P00-01 P02-03 P04-05 P06-07 P08-09 P10-11 P12-13 P14-15
>> // S1: P16-17 P18-19 P20-21 P22-23 P24-25 P26-27 P28-29 P30-31
>> // S2: P32-33 P34-35 P36-37 P38-39 P40-41 P42-43 P44-45 P46-47
>> // S3: P48-49 P50-51 P52-53 P54-55 P56-57 P58-59 P60-61 P62-63
>> // S4: X63-56 X55-48 X47-40 X39-32 X31-24 X23-16 X15-08 X07-00
>> // S5: A63-56 A55-48 A47-40 A39-32 A31-24 A23-16 A15-08 A07-00
>> //
>> // S0 to S5 = Slices 0 to 5
>> // P00 to P63 = Bitmap - pixels 0 to 63
>> // X00 to X63 = always 0 - pixels 0 to 63
>> // A00 to A63 = transparent markers - pixels 0 to 63
>> // 1 means colour, 0 means transparent
>>
>> Signed-off-by: Christopher Harvey <charvey at matrox.com>
>> Signed-off-by: Mathieu Larouche <mathieu.larouche at matrox.com>
>> Acked-by: Julia Lemire <jlemire at matrox.com>
>> Tested-by: Julia Lemire <jlemire at matrox.com>
>
> ping.
I've applied this to drm-next,
Dave.
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