On 10/18/2012 02:34 PM, Thierry Reding wrote:
* PGP Signed by an unknown key
On Thu, Oct 18, 2012 at 02:04:37PM +0800, Mark Zhang wrote:
On 10/17/2012 01:42 PM, Thierry Reding wrote:
Old Signed by an unknown key
On Tue, Oct 16, 2012 at 10:03:56AM -0600, Stephen Warren wrote:
On 10/16/2012 02:18 AM, Mark Zhang wrote:
Hi,
I've made this drm driver worked on Tegra 3(LVDS and HDMI both).
But the code that Thierry
hosts(git://gitorious.org/thierryreding/linux.git) doesn't work
directly. If you build and run it, you'll get a white blank screen on
Tegra 3. I didn't find the root cause but I think this is not caused by
drm driver itself(maybe the PCIE codes?). The main symptom is: some
regulators can't be inited all the time. I tried to build drm driver as
kernel module, after kernel booted, modprobe the drm driver, and you'll
find there are a lot of error prints like this:
=========================================================
[ 21.383529] reg-fixed-voltage 1.regulator: Failed to find supply vin
[ 21.390299] reg-fixed-voltage 1.regulator: Failed to register
regulator: -517
[ 21.397645] platform 1.regulator: Driver reg-fixed-voltage requests
probe deferral
[ 21.405604] platform 2.regulator: Driver reg-fixed-voltage requests
probe deferral
=========================================================
This is normal; it's probe deferral. You'll find that those regulators
initialize correctly later. Hopefully tegra-drm handles this correctly,
and passes that error code through as the result of its probe.
I presume those regulators are for the vdd and pll supplies of the HDMI
output? Those should be properly handled by the tegra_hdmi_probe()
function. Also the way tegra-drm works right now, unless all of the
outputs are registered properly the DRM portion will never even be
initialized.
Not exactly. In hdmi driver, if I try to get/enable vdd & pll
regulators which HDMI needs, error occurs. So currently to make HDMI
working on Tegra 3, we need to temporarily remove these codes.
In fact, there are a lot of this kind of errors, I just pasted some
of them. So there is something in your changes which blocks these
regulators correctly inited cause this issue doesn't exist in
upstream codes.
I don't understand. If you remove the code that enables the regulators,
how can HDMI work at all?
The code in tegra_hdmi_probe() tries to acquire the regulators and
should return an error if it can't. But if HDMI is enabled and the
driver can't access the resources for HDMI, then nothing will be
registered with the DRM core in the first place. That's actually what
the drm_clients list is used for. Basically this defers the DRM
registration until all clients are available.
Stephen gave the answer. We need to enable TI TPS65910 and other related
regulator/gpio settings in kernel config. And I tested just now that it
worked and the HDMI regulator get/enble was OK as well.
Sorry for the confusion.
Thierry
* Unknown Key
* 0x7F3EB3A1
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