On Thu, Aug 29, 2013 at 3:14 PM, Sascha Hauer <[email protected]> wrote: > On Thu, Aug 29, 2013 at 10:59:22AM -0300, Fabio Estevam wrote: >> Since commit b5dc0d10 (drm/imx: kill firstopen callback) the following probe >> failure is seen: >> >> [drm] Supports vblank timestamp caching Rev 1 (10.10.2010). >> [drm] No driver support for vblank timestamp query. >> [drm] Initialized imx-drm 1.0.0 20120507 on minor 0 >> imx-ldb ldb.10: adding encoder failed with -16 >> imx-ldb: probe of ldb.10 failed with error -16 >> imx-ipuv3 2400000.ipu: IPUv3H probed >> imx-ipuv3 2800000.ipu: IPUv3H probed >> imx-ipuv3-crtc imx-ipuv3-crtc.0: adding crtc failed with -16. >> imx-ipuv3-crtc: probe of imx-ipuv3-crtc.0 failed with error -16 >> imx-ipuv3-crtc imx-ipuv3-crtc.1: adding crtc failed with -16. >> imx-ipuv3-crtc: probe of imx-ipuv3-crtc.1 failed with error -16 >> imx-ipuv3-crtc imx-ipuv3-crtc.2: adding crtc failed with -16. >> imx-ipuv3-crtc: probe of imx-ipuv3-crtc.2 failed with error -16 >> imx-ipuv3-crtc imx-ipuv3-crtc.3: adding crtc failed with -16. >> imx-ipuv3-crtc: probe of imx-ipuv3-crtc.3 failed with error -16 >> >> The reason for the probe failure is that now 'imxdrm->references' is >> incremented >> early in imx_drm_driver_load(), so the following checks in imx_drm_add_crtc() >> and imx_drm_add_encoder(): >> >> if (imxdrm->references) { >> ret = -EBUSY; >> goto err_busy; >> } >> >> ,will always fail. >> >> Let the drm core handle the references instead of doing this manually in >> imx-drm. In imx-drm-core the open and close callbacks map to drm_open and >> drm_close, which handle the references via open_count. >> >> After this patch, lvds panel is functional on a mx6qsabrelite board. >> >> Signed-off-by: Fabio Estevam <[email protected]> >> --- >> Changes since v1: >> - Improved commit log by providing an explanation to the probe failure >> - Cc'ed Dave/Daniel >> >> @@ -485,11 +480,6 @@ int imx_drm_add_crtc(struct drm_crtc *crtc, >> >> mutex_lock(&imxdrm->mutex); >> >> - if (imxdrm->references) { >> - ret = -EBUSY; >> - goto err_busy; >> - } > > As I told in v1: Simply removing the code is not an option. We agreed > that we use the drm core reference counting, so you must actually test > for it here...
Yes, we did, but after reading a separate thread on this topic, I learned that drm core does not support it currently. Daniel mentions [1]: "And I wouldn't worry about module unloading and refcounting for now since core drm is terminally broken in that area already anyway" [1] http://www.mail-archive.com/[email protected]/msg43698.html Can't we just apply this patch so that imx-drm can be functional again and fix module unloading/refcount later? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
