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OMAPDSS: HDMI: PHY burnout fix
commit c49d005 upstream. A hardware bug in the OMAP4 HDMI PHY causes physical damage to the board if the HDMI PHY is kept powered on when the cable is not connected. This patch solves the problem by adding hot-plug-detection into the HDMI IP driver. This is not a real HPD support in the sense that nobody else than the IP driver gets to know about the HPD events, but is only meant to fix the HW bug. The strategy is simple: If the display device is turned off by the user, the PHY power is set to OFF. When the display device is turned on by the user, the PHY power is set either to LDOON or TXON, depending on whether the HDMI cable is connected. The reason to avoid PHY OFF when the display device is on, but the cable is disconnected, is that when the PHY is turned OFF, the HDMI IP is not "ticking" and thus the DISPC does not receive pixel clock from the HDMI IP. This would, for example, prevent any VSYNCs from happening, and would thus affect the users of omapdss. By using LDOON when the cable is disconnected we'll avoid the HW bug, but keep the HDMI working as usual from the user's point of view. Signed-off-by: Tomi Valkeinen <firstname.lastname@example.org> Signed-off-by: Greg Kroah-Hartman <email@example.com>
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