From: Daniel Vetter Date: Tue, 1 Apr 2014 20:15:00 +0000 (+0200) Subject: drm/crtc-helper: don't disable disconnected outputs X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=e3d6ddb35f6221859b6054879d186e13a3af351e;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git drm/crtc-helper: don't disable disconnected outputs This is the equivalent change in the crtc helpers as done to the i915 modeset infrastructure in commit b0a2658acb5bf9ca86b4aab011b7106de3af0add Author: Daniel Vetter Date: Tue Dec 18 09:37:54 2012 +0100 drm/i915: don't disable disconnected outputs This was originally introduced to make encoder sharing on radone easier for userspace, but: - It is policy and as such belongs into userspace. E.g. personally I'm fairly annoyed that a flaky cable results in permanent changes of the desktop layout, so I'll kick out DEs which do this. Worse if the kernel also tries to be clever. - It's inconsistent: We only kill disconnected outputs on setCrtc (which userspace might also call when just changing the framebuffer), but not when e.g. we receive a hpd event or in the output poll worker. - It's unexpected behaviour for the userspace driver, at least in the intel ddx we've had tons of bugs where the driver fell over and killed the X session becuase pageflips/vblanks suddenly stopped working. We've had to fix this by wrapping every single setCrtc int a big "recover kms state from the kernel again" operation. - It's suprising for the kernel, too: It took a few mails between Rob, Matt and me for them to notice that little dragon wreaking havoc with the universal plane framebuffer refcounting. - Userspace can cope with it and e.g. Gnome already kills disconnected outputs and reconfigures the desktop automatically. And since there have been no regression reports for the i915 change from over 1 year ago I think all other DEs are also ready. Note that the lines removed in this patch go back to commit a3a0544b2c84e1d7a2022b558ecf66d8c6a8dd93 Author: Dave Airlie Date: Mon Aug 31 15:16:30 2009 +1000 drm/kms: add explicit encoder disable function and detach harder. Unfortunately the patch itself doesn't explain a hole lot about why it was added ... Cc: Matt Roper Cc: Rob Clark Cc: Dave Airlie Cc: Alex Deucher Signed-off-by: Daniel Vetter Signed-off-by: Dave Airlie --- diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c index 8108db95e12b..003924025aa7 100644 --- a/drivers/gpu/drm/drm_crtc_helper.c +++ b/drivers/gpu/drm/drm_crtc_helper.c @@ -289,8 +289,6 @@ static void __drm_helper_disable_unused_functions(struct drm_device *dev) list_for_each_entry(connector, &dev->mode_config.connector_list, head) { if (!connector->encoder) continue; - if (connector->status == connector_status_disconnected) - connector->encoder = NULL; } list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {