Merge lp:~vanvugt/mir/distinguish-crtc-exceptions into lp:~mir-team/mir/trunk

[Daniel van Vugt]

Disambiguate an exception message which could come from three places:
   Output has no associated crtc
with more rich and meaningful information:
   Output <NAME> has no associated CRTC to <ACTION> on

[PS Jenkins bot (ps-jenkins)]

PASSED: Continuous integration, rev:1009
http://jenkins.qa.ubuntu.com/job/mir-ci/1379/
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    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-clang-saucy-amd64-build/1733
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-saucy-amd64-ci/617
        deb: http://jenkins.qa.ubuntu.com/job/mir-saucy-amd64-ci/617/artifact/work/output/*zip*/output.zip

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review: Approve (continuous-integration)

[Robert Ancell (robert-ancell)]

It would be preferrable to have "Unknown(n)" instead of just "Unknown()" - but looks good otherwise.

review: Approve

[Daniel van Vugt (vanvugt)]

It will have a number. connector_name will return "Unknown-N".

[Robert Ancell (robert-ancell)]

It wont have the type which can be useful in debugging, e.g. UnknownM-N. From M we can tell if it's a number we haven't got a name for yet or something worse like memory corruption.

[Daniel van Vugt (vanvugt)]

I don't understand your concern. "Unknown-N" will be unique, unambiguous, and less confusing than "UnknownM-N".

[Robert Ancell (robert-ancell)]

M = conn->connector_type
N = conn->connector_type_id

If M is converted into "Unknown" then there will be no way to know what M was from the log message.

[Daniel van Vugt (vanvugt)]

Oh, right. I suspect M > 14 might be impossible. So it's not a scenario I want to write any more logic for. "Unknown" is good enough.

[Thomas Voß (thomas-voss)]

LGTM, type can be used as an index according to /usr/include/xf86drmMode.h.

review: Approve

=== modified file 'src/server/graphics/gbm/real_kms_output.cpp'
--- src/server/graphics/gbm/real_kms_output.cpp	2013-08-01 07:44:17 +0000
+++ src/server/graphics/gbm/real_kms_output.cpp	2013-08-24 06:33:27 +0000
@@ -89,6 +89,42 @@
     return (encoder->possible_crtcs & (1 << crtc_index));
 }
 
+const char *connector_type_name(uint32_t type)
+{
+    static const int nnames = 15;
+    static const char * const names[nnames] =
+    {   // Ordered according to xf86drmMode.h
+        "Unknown",
+        "VGA",
+        "DVII",
+        "DVID",
+        "DVIA",
+        "Composite",
+        "SVIDEO",
+        "LVDS",
+        "Component",
+        "9PinDIN",
+        "DisplayPort",
+        "HDMIA",
+        "HDMIB",
+        "TV",
+        "eDP"
+    };
+
+    if (type >= nnames)
+        type = 0;
+
+    return names[type];
+}
+
+std::string connector_name(const drmModeConnector *conn)
+{
+    std::string name = connector_type_name(conn->connector_type);
+    name += '-';
+    name += std::to_string(conn->connector_type_id);
+    return name;
+}
+
 }
 
 mgg::RealKMSOutput::RealKMSOutput(int drm_fd, uint32_t connector_id,
@@ -144,7 +180,9 @@
 bool mgg::RealKMSOutput::set_crtc(uint32_t fb_id)
 {
     if (!ensure_crtc())
-        BOOST_THROW_EXCEPTION(std::runtime_error("Output has no associated crtc"));
+        BOOST_THROW_EXCEPTION(std::runtime_error("Output " +
+            connector_name(connector.get()) +
+            " has no associated CRTC to set a framebuffer on"));
 
     auto ret = drmModeSetCrtc(drm_fd, current_crtc->crtc_id,
                               fb_id, fb_offset.dx.as_int(), fb_offset.dy.as_int(),
@@ -163,7 +201,9 @@
 bool mgg::RealKMSOutput::schedule_page_flip(uint32_t fb_id)
 {
     if (!current_crtc)
-        BOOST_THROW_EXCEPTION(std::runtime_error("Output has no associated crtc"));
+        BOOST_THROW_EXCEPTION(std::runtime_error("Output " +
+            connector_name(connector.get()) +
+            " has no associated CRTC to schedule page flips on"));
 
     return page_flipper->schedule_flip(current_crtc->crtc_id, fb_id);
 }
@@ -171,7 +211,9 @@
 void mgg::RealKMSOutput::wait_for_page_flip()
 {
     if (!current_crtc)
-        BOOST_THROW_EXCEPTION(std::runtime_error("Output has no associated crtc"));
+        BOOST_THROW_EXCEPTION(std::runtime_error("Output " +
+            connector_name(connector.get()) +
+            " has no associated CRTC to wait on"));
 
     page_flipper->wait_for_flip(current_crtc->crtc_id);
 }