Hi Liviu, On 6/29/2023 3:21 PM, Liviu Dudau wrote: > Hi Faiz, > > Thanks for the patch and for addressing what was at some moment on my "nice to > improve / cleanup" list. Sorry for the delay in responding, I had to revive > the bits of an old setup to be able to test this properly, with 2 encoders > attached. > > On Wed, Jun 21, 2023 at 02:11:16PM +0530, Faiz Abbas wrote: >> The Komeda driver always expects the remote connector node to initialize >> an encoder. It uses the component aggregator framework which consists >> of component->bind() calls used to initialize the remote encoder and attach >> it to the crtc. This is different from other drm implementations which expect >> the display driver to supply a crtc and connect an encoder to it. > I think both approaches are valid in DRM. We don't want to remove the component > framework because it is doing the wrong thing, but because we cannot use it > with drivers that implement the drm_bridge API. Given that we usually pair with > a component encoder that also implements a drm_bridge, dropping support for > component framework should not affect the users of the driver. Sounds good. I will update the commit message to emphasize the bridge API. >> Remove all component framework calls from the komeda driver and declare and >> attach an encoder inside komeda_crtc_add(). > Unfortunately you haven't removed all component framework calls. The hint for > that is that you have not removed the #include <linux/component.h> line from > any of the files. Specifically, komeda_kms_attach()/detach() still calls > component_unbind_all() which will crash with your patch applied. Good catch. Will remove that stuff in v2. >> The remote connector driver has to implement the DRM bridge APIs which >> can be used to glue the encoder to the remote connector. >> >> Signed-off-by: Faiz Abbas <faiz.abbas@xxxxxxx> >> --- >> .../gpu/drm/arm/display/komeda/komeda_crtc.c | 22 +++++++- >> .../gpu/drm/arm/display/komeda/komeda_drv.c | 56 ++----------------- >> .../gpu/drm/arm/display/komeda/komeda_kms.c | 4 -- >> .../gpu/drm/arm/display/komeda/komeda_kms.h | 3 + >> 4 files changed, 30 insertions(+), 55 deletions(-) >> >> diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c >> index cea3fd5772b57..144736a69b0ee 100644 >> --- a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c >> +++ b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c >> @@ -12,6 +12,8 @@ >> #include <drm/drm_atomic_helper.h> >> #include <drm/drm_print.h> >> #include <drm/drm_vblank.h> >> +#include <drm/drm_simple_kms_helper.h> >> +#include <drm/drm_bridge.h> >> >> #include "komeda_dev.h" >> #include "komeda_kms.h" >> @@ -612,9 +614,11 @@ static int komeda_crtc_add(struct komeda_kms_dev *kms, >> struct komeda_crtc *kcrtc) >> { >> struct drm_crtc *crtc = &kcrtc->base; >> + struct drm_device *base = &kms->base; >> + struct drm_bridge *bridge; >> int err; >> >> - err = drm_crtc_init_with_planes(&kms->base, crtc, >> + err = drm_crtc_init_with_planes(base, crtc, >> get_crtc_primary(kms, kcrtc), NULL, >> &komeda_crtc_funcs, NULL); >> if (err) >> @@ -626,6 +630,22 @@ static int komeda_crtc_add(struct komeda_kms_dev *kms, >> >> drm_crtc_enable_color_mgmt(crtc, 0, true, KOMEDA_COLOR_LUT_SIZE); > I would move this line after the bridges are being initialised, just in case in the future > colour management will propagate some info down to the bridges. Sure. I'll move it down. . . . >> }; >> >> /** >> -- >> 2.25.1 >> > Code looks good and turns out swapping drm_bridge for component framework is not that painful. If you send v2 > with the comments addressed I should be able to test it now and review the patch much sooner. > > One issue I have observed from my testing of your patch is that on `rmmod komeda` we fail to disable the > interrupts after drm_kms_helper_poll_fini() call in komeda_kms_detach(), then we NULL the drm->dev_private > before we get an interrupt which causes komeda_kms_irq_handler() to access the NULL pointer. This is not > something caused by your patch, but if you want to test module removal I think you should be aware of this. I'll keep this in mind while testing. Thanks, Faiz