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    mach64: fix image corruption due to reading accelerator registers · c09bcc91
    Mikulas Patocka 提交于
    Reading the registers without waiting for engine idle returns
    unpredictable values. These unpredictable values result in display
    corruption - if atyfb_imageblit reads the content of DP_PIX_WIDTH with the
    bit DP_HOST_TRIPLE_EN set (from previous invocation), the driver would
    never ever clear the bit, resulting in display corruption.
    
    We don't want to wait for idle because it would degrade performance, so
    this patch modifies the driver so that it never reads accelerator
    registers.
    
    HOST_CNTL doesn't have to be read, we can just write it with
    HOST_BYTE_ALIGN because no other part of the driver cares if
    HOST_BYTE_ALIGN is set.
    
    DP_PIX_WIDTH is written in the functions atyfb_copyarea and atyfb_fillrect
    with the default value and in atyfb_imageblit with the value set according
    to the source image data.
    Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
    Reviewed-by: NVille Syrjälä <syrjala@sci.fi>
    Cc: stable@vger.kernel.org
    Signed-off-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
    c09bcc91
mach64_accel.c 11.6 KB