From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Date: Wed, 24 Dec 2014 17:13:20 +0100 Subject: [U-Boot] [PATCH 5/6] sunxi: video: Give hotplug-detect (hpd) signal some time to show up In-Reply-To: <549A2430.5040609@openmailbox.org> References: <1419086525-7735-1-git-send-email-hdegoede@redhat.com> <1419086525-7735-6-git-send-email-hdegoede@redhat.com> <549A2430.5040609@openmailbox.org> Message-ID: <549AE620.9060003@redhat.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi, On 24-12-14 03:25, B.R. Oake wrote: > On 20/12/14 14:42, Hans de Goede wrote: >> When using a hdmi powered hdmi to vga dongle, and cold booting a sunxi >> device, the hpd detect code would not see the dongle (until a warm reboot), >> because the dongle needs some time to boot. >> >> Testing has shown that this dongle needs 213ms to respond on a cold boot, >> so wait up to 300ms for a hpd signal to show up before giving up. > > Hi Hans, > > I'm using a similar convertor but it sometimes takes longer to be ready, > depending on what screen is connected. With an old VGA monitor, I've seen > it take up to 1230ms before returning the HPD signal, presumably while it > collects information from the monitor. > > Would it be acceptable to increase the wait from 300ms to about 1500ms? That means delaying the boot by another 1.2 seconds on all machines which have hdmi without a cable plugged in. I'm not sure I'm a fan of that. Ian, what is your take on this ? Regards, Hans