Commit c39b0695 authored by Russell King's avatar Russell King Committed by Dave Airlie
Browse files

DRM: armada: fix corruption while loading cursors



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.

Cc: <stable@vger.kernel.org> # 3.13
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 9f97ba80
......@@ -679,6 +679,7 @@ static void armada_load_cursor_argb(void __iomem *base, uint32_t *pix,
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;
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment