Re: [PATCH v3 RESEND] OMAPDSS: DISPC: Improvements to DIGIT sync signal selection

[Ricardo Neri <ricardo.neri@ti.com>]

On 08/01/2012 01:28 AM, Tomi Valkeinen wrote:
> On Tue, 2012-07-31 at 18:56 -0500, Ricardo Neri wrote:
>> DSS code wrongly assumes that VENC is always available as source for the external
>> sync signal for the display controller DIGIT channel. One cannot blindly write/read
>> the value of DSS_CONTROL[15] as in certain processors (e.g., OMAP5) this operation
>> may not be valid. If the the sync source is not read correctly, the callers of
>> dss_get_hdmi_venc_clk_source might make wrong assumptions about, for instance,
>> video timings.
>>
>> Logic is added to correctly get the sync signal based on the available displays
>> in the DIGIT channel. The source is set only if both VENC and HDMI are supported.
>>
>> Signed-off-by: Ricardo Neri <ricardo.neri@ti.com>
>> ---
>> v3: instead of BUG_ON calls, select only if both VENC and HDMI are available.
>
> I think they do make sense. For example, if somebody calls this function
> and tries to set the switch to VENC on an OMAP that doesn't have VENC,
> something is wrong. Your new version just skips the register write in
> that case, which is ok, but I think we should also yell that something
> is wrong.
>
> I'd have the BUG_ONs there, but change them to WARN_ON. I think we
> should generally try to have less BUGs and more WARNs. Also, please keep
> the comment about the bits being written (VENC_HDMI_SWITCH), it helps to
> understand the code.

I will resubmit based on these comments.
>
>   Tomi
>