kernel/linux.git/drivers/usb/core/usb.c, branch linux-6.0.y

usb/core: fix repeated words in comments

2022-07-27T12:32:29+00:00

Delete the redundant word 'the'. Signed-off-by: Jilin Yuan Link: https://lore.kernel.org/r/20220716132403.35270-1-yuanjilin@cdjrlc.com Signed-off-by: Greg Kroah-Hartman

USB: core: Update kerneldoc for usb_get_dev() and usb_get_intf()

2022-02-25T15:53:41+00:00

The kerneldoc for usb_get_dev() and usb_get_intf() says that drivers should always refcount the references they hold for the usb_device or usb_interface structure, respectively. But this is an overstatement: In many cases drivers do not access these references after they have been unbound, and in such cases refcounting is unnecessary. This patch updates the kerneldoc for the two routines, explaining when a driver does not need to increment and decrement the refcount. This should help dispel misconceptions which might otherwise afflict programmers new to the USB subsystem. Signed-off-by: Alan Stern Link: https://lore.kernel.org/r/Yhjp4Rp9Alipmwtq@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman

usb: Remove usb_for_each_port()

2021-12-30T11:13:04+00:00

There are no more users for the function. Reviewed-by: Andy Shevchenko Acked-by: Rafael J. Wysocki Signed-off-by: Heikki Krogerus Link: https://lore.kernel.org/r/20211223082432.45653-1-heikki.krogerus@linux.intel.com Signed-off-by: Greg Kroah-Hartman

usb: Iterator for ports

2021-04-09T14:00:00+00:00

Introducing usb_for_each_port(). It works the same way as usb_for_each_dev(), but instead of going through every USB device in the system, it walks through the USB ports in the system. Acked-by: Alan Stern Signed-off-by: Heikki Krogerus Link: https://lore.kernel.org/r/20210407065555.88110-4-heikki.krogerus@linux.intel.com Signed-off-by: Greg Kroah-Hartman

Merge 5.12-rc3 into usb-next

2021-03-15T07:45:20+00:00

We want the USB fixes in here as well. Signed-off-by: Greg Kroah-Hartman

drm: Use USB controller's DMA mask when importing dmabufs

2021-03-11T10:11:33+00:00

USB devices cannot perform DMA and hence have no dma_mask set in their device structure. Therefore importing dmabuf into a USB-based driver fails, which breaks joining and mirroring of display in X11. For USB devices, pick the associated USB controller as attachment device. This allows the DRM import helpers to perform the DMA setup. If the DMA controller does not support DMA transfers, we're out of luck and cannot import. Our current USB-based DRM drivers don't use DMA, so the actual DMA device is not important. Tested by joining/mirroring displays of udl and radeon under Gnome/X11. v8: * release dmadev if device initialization fails (Noralf) * fix commit description (Noralf) v7: * fix use-before-init bug in gm12u320 (Dan) v6: * implement workaround in DRM drivers and hold reference to DMA device while USB device is in use * remove dev_is_usb() (Greg) * collapse USB helper into usb_intf_get_dma_device() (Alan) * integrate Daniel's TODO statement (Daniel) * fix typos (Greg) v5: * provide a helper for USB interfaces (Alan) * add FIXME item to documentation and TODO list (Daniel) v4: * implement workaround with USB helper functions (Greg) * use struct usb_device->bus->sysdev as DMA device (Takashi) v3: * drop gem_create_object * use DMA mask of USB controller, if any (Daniel, Christian, Noralf) v2: * move fix to importer side (Christian, Daniel) * update SHMEM and CMA helpers for new PRIME callbacks Signed-off-by: Thomas Zimmermann Fixes: 6eb0233ec2d0 ("usb: don't inherity DMA properties for USB devices") Tested-by: Pavel Machek Reviewed-by: Greg Kroah-Hartman Acked-by: Christian König Acked-by: Daniel Vetter Acked-by: Noralf Trønnes Cc: Christoph Hellwig Cc: Greg Kroah-Hartman Cc: # v5.10+ Signed-off-by: Thomas Zimmermann Link: https://patchwork.freedesktop.org/patch/msgid/20210303133229.3288-1-tzimmermann@suse.de Signed-off-by: Maarten Lankhorst

USB: core: no need to save usb_devices_root

2021-03-10T08:37:15+00:00

There is no need to save the usb_devices debugfs file as we only need it when removing it, so have the debugfs code look it up when it is needed instead, saving the storage. Link: https://lore.kernel.org/r/YCubCA/trHAF7PtF@kroah.com Signed-off-by: Greg Kroah-Hartman

usb: core: Replace in_interrupt() in comments

2020-10-28T11:32:59+00:00

The usage of in_interrupt() in drivers is phased out for various reasons. Various comments use !in_interrupt() to describe calling context for functions which might sleep. That's wrong because the calling context has to be preemptible task context, which is not what !in_interrupt() describes. Replace !in_interrupt() with more accurate plain text descriptions. The comment for usb_hcd_poll_rh_status() is misleading as this function is called from all kinds of contexts including preemptible task context. Remove it as there is obviously no restriction. Signed-off-by: Ahmed S. Darwish Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Acked-by: Alan Stern Cc: linux-usb@vger.kernel.org Link: https://lore.kernel.org/r/20201019101110.851821025@linutronix.de Signed-off-by: Greg Kroah-Hartman

usb: don't inherity DMA properties for USB devices

2020-09-17T16:43:25+00:00

As the comment in usb_alloc_dev correctly states, drivers can't use the DMA API on usb device, and at least calling dma_set_mask on them is highly dangerous. Unlike what the comment states upper level drivers also can't really use the presence of a dma mask to check for DMA support, as the dma_mask is set by default for most busses. Setting the dma_mask comes from "[PATCH] usbcore dma updates (and doc)" in BitKeeper times, as it seems like it was primarily for setting the NETIF_F_HIGHDMA flag in USB drivers, something that has long been fixed up since. Setting the dma_pfn_offset comes from commit b44bbc46a8bb ("usb: core: setup dma_pfn_offset for USB devices and, interfaces"), which worked around the fact that the scsi_calculate_bounce_limits functions wasn't going through the proper driver interface to query DMA information, but that function was removed in commit 21e07dba9fb1 ("scsi: reduce use of block bounce buffers") years ago. Signed-off-by: Christoph Hellwig Reviewed-by: Greg Kroah-Hartman

USB: Fix up terminology

2020-07-01T12:04:04+00:00

USB is a HOST/DEVICE protocol, as per the specification and all documentation. Fix up terms that are not applicable to make things match up with the terms used through the rest of the USB stack. Signed-off-by: Greg Kroah-Hartman Acked-by: Felipe Balbi Link: https://lore.kernel.org/r/20200630174123.GA1906678@kroah.com Signed-off-by: Greg Kroah-Hartman