| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.14 101/158] DRM: armada: fix corruption while loading cursors | Date | Sun, 4 May 2014 11:40:10 -0400 |
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3.14-stable review patch. If anyone has any objections, please let me know.
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From: Russell King <rmk+kernel@arm.linux.org.uk>
commit c39b06951f1dc2e384650288676c5b7dcc0ec92c upstream.
Loading cursors to the LCD controller's SRAM can be corrupted when the configured pixel clock is relatively slow. This seems to be caused when we write back-to-back to the SRAM registers.
There doesn't appear to be any status register we can read to check when an access has completed.
Inserting a dummy read between the writes appears to fix the problem.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/gpu/drm/armada/armada_crtc.c | 1 + 1 file changed, 1 insertion(+)
--- a/drivers/gpu/drm/armada/armada_crtc.c +++ b/drivers/gpu/drm/armada/armada_crtc.c @@ -678,6 +678,7 @@ static void armada_load_cursor_argb(void base + LCD_SPU_SRAM_WRDAT); writel_relaxed(addr | SRAM_WRITE, base + LCD_SPU_SRAM_CTRL); + readl_relaxed(base + LCD_SPU_HWC_OVSA_HPXL_VLN); addr += 1; if ((addr & 0x00ff) == 0) addr += 0xf00;
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