From: Oliver Neukum <oneukum@suse.com>
To: Alan Stern <stern@rowland.harvard.edu>,
Haowen Tu <tuhaowen@uniontech.com>
Cc: hansg@kernel.org, gregkh@linuxfoundation.org,
kernel@uniontech.com, laurent.pinchart@ideasonboard.com,
lenb@kernel.org, linux-kernel@vger.kernel.org,
linux-media@vger.kernel.org, linux-pm@vger.kernel.org,
linux-usb@vger.kernel.org, mchehab@kernel.org, pavel@kernel.org,
rafael@kernel.org
Subject: Re: [PATCH v4 4/4] media: uvcvideo: defer streaming restart after hibernation snapshot
Date: Wed, 29 Jul 2026 16:43:44 +0200 [thread overview]
Message-ID: <5d36c6a8-bbc9-4d5f-8670-2993bdeb857f@suse.com> (raw)
In-Reply-To: <0e22e9d4-da39-4d3f-9492-5c74295be312@rowland.harvard.edu>
On 29.07.26 16:08, Alan Stern wrote:
> You're missing an important fact: If something goes wrong during the
> hibernation transition (for example, if the kernel's memory image can't
> be stored to disk) then there will be no RESTORE phase. Following the
> THAW phase, the system will return to normal operation.
Right, but that does not need to mean that the driver has to be operational
at the THAW phase. It has to be operational before userland is unfrozen
again at the latest. The difficulty how the driver learns that the system
will not power down remains to be solved.
> For this reason, during THAW drivers must not assume that the system is
> about to power down.
True. For this reason the patch introduces a notifier queue.
Now, that you make me think about that it seems to be inelegant, as this throws
away the proper order of the device tree. It seems to me that we should
bite the bullet and go for the big solution:
Split the THAW phase in two, like a THAW_WRITEOUT and an optional
THAW_BAILOUT that is called only when the system does not power down.
Regards
Oliver
next prev parent reply other threads:[~2026-07-29 14:43 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-28 8:05 [PATCH 0/2] PM: hibernate: add helper to detect image-write phase Haowen Tu
2026-04-28 8:05 ` [PATCH 1/2] PM: hibernate: add pm_hibernation_storing_image() helper Haowen Tu
2026-05-26 13:43 ` Rafael J. Wysocki
2026-04-28 8:05 ` [PATCH 2/2] media: uvcvideo: skip resume when writing hibernation image Haowen Tu
2026-04-28 8:36 ` Oliver Neukum
2026-04-28 8:58 ` Haowen Tu
2026-04-28 9:13 ` Laurent Pinchart
2026-04-29 1:15 ` Haowen Tu
2026-04-29 1:16 ` Haowen Tu
2026-05-28 8:18 ` [PATCH v2 0/2] PM: hibernate: skip UVC resume after snapshot Haowen Tu
2026-05-28 8:18 ` [PATCH v2 1/2] PM: hibernate: add pm_hibernation_snapshot_done() helper Haowen Tu
2026-06-01 18:22 ` Rafael J. Wysocki
2026-06-02 3:24 ` Haowen Tu
2026-06-18 1:31 ` [PATCH v3 0/3] PM: hibernate: skip UVC streaming restart after snapshot Haowen Tu
2026-06-18 1:31 ` [PATCH v3 1/3] PM: hibernate: clear in_suspend before freeing the snapshot Haowen Tu
2026-07-22 15:37 ` Rafael J. Wysocki (Intel)
2026-06-18 1:31 ` [PATCH v3 2/3] PM: hibernate: add pm_hibernation_snapshot_done() helper Haowen Tu
2026-07-22 15:40 ` Rafael J. Wysocki (Intel)
2026-06-18 1:31 ` [PATCH v3 3/3] media: uvcvideo: skip streaming restart after hibernation snapshot Haowen Tu
2026-07-22 20:06 ` Laurent Pinchart
2026-07-23 1:39 ` Haowen Tu
2026-07-23 8:46 ` Laurent Pinchart
2026-07-29 7:11 ` [PATCH v4 0/4] PM: hibernate: defer UVC streaming restart after snapshot Haowen Tu
2026-07-29 7:11 ` [PATCH v4 1/4] PM: hibernate: clear in_suspend before freeing the snapshot Haowen Tu
2026-07-29 7:11 ` [PATCH v4 2/4] PM: hibernate: add pm_hibernation_snapshot_done() helper Haowen Tu
2026-07-29 7:11 ` [PATCH v4 3/4] PM: hibernate: notify on image write failure Haowen Tu
2026-07-29 7:11 ` [PATCH v4 4/4] media: uvcvideo: defer streaming restart after hibernation snapshot Haowen Tu
2026-07-29 7:29 ` Hans de Goede
2026-07-29 7:56 ` Haowen Tu
2026-07-29 14:08 ` Alan Stern
2026-07-29 14:43 ` Oliver Neukum [this message]
2026-07-29 14:54 ` Alan Stern
2026-07-30 13:16 ` Laurent Pinchart
2026-07-30 14:29 ` Alan Stern
2026-07-30 15:38 ` Laurent Pinchart
2026-07-31 1:30 ` Haowen Tu
2026-09-03 2:14 ` [PATCH v5 0/4] PM: hibernate: skip unnecessary THAW resume Haowen Tu
2026-09-03 2:14 ` [PATCH v5 1/4] PM: hibernate: clear in_suspend before freeing the snapshot Haowen Tu
2026-09-03 2:14 ` [PATCH v5 2/4] PM: hibernate: add pm_hibernation_snapshot_done() helper Haowen Tu
2026-09-03 2:14 ` [PATCH v5 3/4] PM: hibernate: allow devices to skip post-snapshot THAW Haowen Tu
2026-09-03 2:14 ` [PATCH v5 4/4] media: uvcvideo: skip post-snapshot hibernation THAW Haowen Tu
2026-05-28 8:18 ` [PATCH v2 2/2] media: uvcvideo: skip resume after hibernation snapshot Haowen Tu
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