From: "Michel Dänzer" <michel@daenzer.net> To: Keith Packard <keithp@keithp.com>, Dave Airlie <airlied@redhat.com>, Daniel Vetter <daniel@ffwll.ch> Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH 1/3] drm: Widen vblank count to 64 bits. Change vblank time precision to ns Date: Fri, 7 Jul 2017 10:34:12 +0900 [thread overview] Message-ID: <f57962d7-8741-a455-fc37-09c50c04e902@daenzer.net> (raw) In-Reply-To: <86o9sxd2sw.fsf@keithp.com> [-- Attachment #1.1: Type: text/plain, Size: 1528 bytes --] On 07/07/17 12:04 AM, Keith Packard wrote: > Michel Dänzer <michel@daenzer.net> writes: > >>> @@ -317,6 +317,9 @@ int via_driver_irq_postinstall(struct drm_device *dev) >>> if (!dev_priv) >>> return -EINVAL; >>> >>> + if (dev->driver->get_vblank_counter) >>> + dev->max_vblank_count = 0xffffffff; >> >> What's the purpose of this? All drivers providing get_vblank_counter >> should already initialize max_vblank_count correctly. > > Yeah, I couldn't prove that this driver did that, Which driver? > and as Daniel says, we haven't ever audited the drivers to make sure > they do. I don't think that's what he meant, rather that with the change above, all drivers have to be audited to make sure the added assignment doesn't clobber an earlier assignment by the driver. > We have a check to see that they don't set max_vblank_count if they > don't provide a get function, but I can't find the matching check for > drivers that do provide a function and aren't setting max_vblank_count. I don't think that's necessary, see drm_update_vblank_count: if (dev->max_vblank_count != 0) { /* trust the hw counter when it's around */ diff = (cur_vblank - vblank->last) & dev->max_vblank_count; } else [...] The hardware vblank counter is only used for updating the DRM vblank counter if dev->max_vblank_count != 0. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer [-- Attachment #2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 224 bytes --]
WARNING: multiple messages have this Message-ID (diff)
From: "Michel Dänzer" <michel@daenzer.net> To: Keith Packard <keithp@keithp.com>, Dave Airlie <airlied@redhat.com>, Daniel Vetter <daniel@ffwll.ch> Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH 1/3] drm: Widen vblank count to 64 bits. Change vblank time precision to ns Date: Fri, 7 Jul 2017 10:34:12 +0900 [thread overview] Message-ID: <f57962d7-8741-a455-fc37-09c50c04e902@daenzer.net> (raw) In-Reply-To: <86o9sxd2sw.fsf@keithp.com> [-- Attachment #1.1.1: Type: text/plain, Size: 1528 bytes --] On 07/07/17 12:04 AM, Keith Packard wrote: > Michel Dänzer <michel@daenzer.net> writes: > >>> @@ -317,6 +317,9 @@ int via_driver_irq_postinstall(struct drm_device *dev) >>> if (!dev_priv) >>> return -EINVAL; >>> >>> + if (dev->driver->get_vblank_counter) >>> + dev->max_vblank_count = 0xffffffff; >> >> What's the purpose of this? All drivers providing get_vblank_counter >> should already initialize max_vblank_count correctly. > > Yeah, I couldn't prove that this driver did that, Which driver? > and as Daniel says, we haven't ever audited the drivers to make sure > they do. I don't think that's what he meant, rather that with the change above, all drivers have to be audited to make sure the added assignment doesn't clobber an earlier assignment by the driver. > We have a check to see that they don't set max_vblank_count if they > don't provide a get function, but I can't find the matching check for > drivers that do provide a function and aren't setting max_vblank_count. I don't think that's necessary, see drm_update_vblank_count: if (dev->max_vblank_count != 0) { /* trust the hw counter when it's around */ diff = (cur_vblank - vblank->last) & dev->max_vblank_count; } else [...] The hardware vblank counter is only used for updating the DRM vblank counter if dev->max_vblank_count != 0. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer [-- Attachment #1.2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 224 bytes --] [-- Attachment #2: Type: text/plain, Size: 160 bytes --] _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2017-07-07 1:34 UTC|newest] Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-07-05 22:10 [PATCH 0/3] drm: Add CRTC-id based ioctls for vblank query/event Keith Packard 2017-07-05 22:10 ` Keith Packard 2017-07-05 22:10 ` [PATCH 1/3] drm: Widen vblank count to 64 bits. Change vblank time precision to ns Keith Packard 2017-07-05 22:10 ` Keith Packard 2017-07-06 7:19 ` Daniel Vetter 2017-07-06 7:19 ` Daniel Vetter 2017-07-06 14:59 ` Keith Packard 2017-07-06 14:59 ` Keith Packard 2017-07-07 12:16 ` Daniel Vetter 2017-07-07 12:16 ` Daniel Vetter 2017-07-25 20:54 ` Keith Packard 2017-07-25 20:54 ` Keith Packard 2017-07-06 7:45 ` Michel Dänzer 2017-07-06 7:45 ` Michel Dänzer 2017-07-06 8:05 ` Michel Dänzer 2017-07-06 8:05 ` Michel Dänzer 2017-07-06 15:11 ` Keith Packard 2017-07-06 15:04 ` Keith Packard 2017-07-06 15:04 ` Keith Packard 2017-07-07 1:34 ` Michel Dänzer [this message] 2017-07-07 1:34 ` Michel Dänzer 2017-07-07 2:05 ` Michel Dänzer 2017-07-07 2:05 ` Michel Dänzer 2017-07-05 22:10 ` [PATCH 2/3] drm: Reorganize drm_pending_event to support future event types Keith Packard 2017-07-05 22:10 ` Keith Packard 2017-07-06 7:30 ` Daniel Vetter 2017-07-06 15:36 ` Keith Packard 2017-07-06 15:36 ` Keith Packard 2017-07-07 12:05 ` Daniel Vetter 2017-07-07 12:05 ` Daniel Vetter 2017-07-05 22:10 ` [PATCH 3/3] drm: Add CRTC_GET_SEQUENCE and CRTC_QUEUE_SEQUENCE ioctls Keith Packard 2017-07-05 22:10 ` Keith Packard 2017-07-06 7:53 ` Daniel Vetter 2017-07-06 10:16 ` Ville Syrjälä 2017-07-06 10:16 ` Ville Syrjälä 2017-07-06 11:04 ` Daniel Vetter 2017-07-06 14:08 ` Ville Syrjälä 2017-07-06 16:28 ` Keith Packard 2017-07-06 16:28 ` Keith Packard 2017-07-06 17:59 ` Ville Syrjälä 2017-07-06 17:59 ` Ville Syrjälä 2017-07-06 18:22 ` Keith Packard 2017-07-06 18:22 ` Keith Packard 2017-07-06 18:59 ` Ville Syrjälä 2017-07-06 18:59 ` Ville Syrjälä 2017-07-06 19:46 ` Keith Packard 2017-07-06 19:46 ` Keith Packard 2017-07-06 16:27 ` Keith Packard 2017-07-06 16:27 ` Keith Packard 2017-07-06 21:49 ` Daniel Vetter 2017-07-06 21:49 ` Daniel Vetter 2017-08-01 5:03 ` [PATCH 0/3] drm: Add CRTC-id based ioctls for vblank query/event Keith Packard 2017-08-01 5:03 ` Keith Packard 2017-08-01 5:03 ` [PATCH 1/3] drm: Widen vblank UAPI to 64 bits. Change vblank time to ktime_t [v2] Keith Packard 2017-08-01 5:03 ` Keith Packard 2017-08-02 8:53 ` Daniel Vetter 2017-08-02 8:53 ` Daniel Vetter 2017-08-02 9:41 ` Michel Dänzer 2017-08-02 9:41 ` Michel Dänzer 2017-08-06 17:35 ` Keith Packard 2017-08-06 17:35 ` Keith Packard 2017-08-01 5:03 ` [PATCH 2/3] drm: Reorganize drm_pending_event to support future event types [v2] Keith Packard 2017-08-02 9:05 ` Daniel Vetter 2017-08-01 5:03 ` [PATCH 3/3] drm: Add CRTC_GET_SEQUENCE and CRTC_QUEUE_SEQUENCE ioctls [v2] Keith Packard 2017-08-01 5:03 ` Keith Packard 2017-08-02 9:25 ` Daniel Vetter 2017-08-02 9:25 ` Daniel Vetter 2017-08-06 3:32 ` Keith Packard 2017-08-06 3:32 ` Keith Packard 2017-08-07 3:02 ` Michel Dänzer 2017-08-07 3:02 ` Michel Dänzer 2017-08-07 8:34 ` Daniel Vetter 2017-08-07 8:34 ` Daniel Vetter 2017-10-09 17:18 ` Keith Packard 2017-10-09 17:18 ` Keith Packard 2017-10-10 8:55 ` Daniel Vetter 2017-10-10 8:55 ` Daniel Vetter 2017-08-02 9:45 ` Michel Dänzer 2017-08-06 3:42 ` Keith Packard 2017-08-06 3:42 ` Keith Packard 2017-08-07 3:03 ` Michel Dänzer 2017-08-07 3:03 ` Michel Dänzer
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