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Subject[PATCH 3.14 101/158] DRM: armada: fix corruption while loading cursors
Date
3.14-stable review patch.  If anyone has any objections, please let me know.

------------------

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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