cirrus: handle negative pitch in cirrus_invalidate_region()

cirrus_invalidate_region() calls memory_region_set_dirty()
on a per-line basis, always ranging from off_begin to
off_begin+bytesperline. With a negative pitch off_begin
marks the top most used address and thus we need to do an
initial shift backwards by a line for negative pitches of
backward blits, otherwise the first iteration covers the
line going from the start offset forwards instead of
backwards.
Additionally since the start address is inclusive, if we
shift by a full `bytesperline` we move to the first address
*not* included in the blit, so we only shift by one less
than bytesperline.

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
Message-id: 1485352137-29367-1-git-send-email-w.bumiller@proxmox.com

[ kraxel: codestyle fixes ]

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
(cherry picked from commit f153b563f8)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
stable-2.8
Wolfgang Bumiller 2017-01-25 14:48:57 +01:00 committed by Michael Roth
parent 1a184c3af3
commit 5d26f91c89
1 changed files with 5 additions and 0 deletions

View File

@ -660,9 +660,14 @@ static void cirrus_invalidate_region(CirrusVGAState * s, int off_begin,
int off_cur;
int off_cur_end;
if (off_pitch < 0) {
off_begin -= bytesperline - 1;
}
for (y = 0; y < lines; y++) {
off_cur = off_begin;
off_cur_end = (off_cur + bytesperline) & s->cirrus_addr_mask;
assert(off_cur_end >= off_cur);
memory_region_set_dirty(&s->vga.vram, off_cur, off_cur_end - off_cur);
off_begin += off_pitch;
}