diff options
| -rw-r--r-- | drivers/gpu/vga/vga_switcheroo.c | 285 | ||||
| -rw-r--r-- | include/linux/vga_switcheroo.h | 85 |
2 files changed, 353 insertions, 17 deletions
diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c index 21060668fd25..b19a72f7ac7c 100644 --- a/drivers/gpu/vga/vga_switcheroo.c +++ b/drivers/gpu/vga/vga_switcheroo.c @@ -1,20 +1,31 @@ /* + * vga_switcheroo.c - Support for laptop with dual GPU using one set of outputs + * * Copyright (c) 2010 Red Hat Inc. * Author : Dave Airlie <airlied@redhat.com> * + * Copyright (c) 2015 Lukas Wunner <lukas@wunner.de> * - * Licensed under GPLv2 + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: * - * vga_switcheroo.c - Support for laptop with dual GPU using one set of outputs + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. * - * Switcher interface - methods require for ATPX and DCM - * - switchto - this throws the output MUX switch - * - discrete_set_power - sets the power state for the discrete card + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS + * IN THE SOFTWARE. * - * GPU driver interface - * - set_gpu_state - this should do the equiv of s/r for the card - * - this should *not* set the discrete power state - * - switch_check - check if the device is in a position to switch now */ #define pr_fmt(fmt) "vga_switcheroo: " fmt @@ -33,6 +44,61 @@ #include <linux/vgaarb.h> +/** + * DOC: Overview + * + * vga_switcheroo is the Linux subsystem for laptop hybrid graphics. + * These come in two flavors: + * + * * muxed: Dual GPUs with a multiplexer chip to switch outputs between GPUs. + * * muxless: Dual GPUs but only one of them is connected to outputs. + * The other one is merely used to offload rendering, its results + * are copied over PCIe into the framebuffer. On Linux this is + * supported with DRI PRIME. + * + * Hybrid graphics started to appear in the late Naughties and were initially + * all muxed. Newer laptops moved to a muxless architecture for cost reasons. + * A notable exception is the MacBook Pro which continues to use a mux. + * Muxes come with varying capabilities: Some switch only the panel, others + * can also switch external displays. Some switch all display pins at once + * while others can switch just the DDC lines. (To allow EDID probing + * for the inactive GPU.) Also, muxes are often used to cut power to the + * discrete GPU while it is not used. + * + * DRM drivers register GPUs with vga_switcheroo, these are heretoforth called + * clients. The mux is called the handler. Muxless machines also register a + * handler to control the power state of the discrete GPU, its ->switchto + * callback is a no-op for obvious reasons. The discrete GPU is often equipped + * with an HDA controller for the HDMI/DP audio signal, this will also + * register as a client so that vga_switcheroo can take care of the correct + * suspend/resume order when changing the discrete GPU's power state. In total + * there can thus be up to three clients: Two vga clients (GPUs) and one audio + * client (on the discrete GPU). The code is mostly prepared to support + * machines with more than two GPUs should they become available. + * The GPU to which the outputs are currently switched is called the + * active client in vga_switcheroo parlance. The GPU not in use is the + * inactive client. + */ + +/** + * struct vga_switcheroo_client - registered client + * @pdev: client pci device + * @fb_info: framebuffer to which console is remapped on switching + * @pwr_state: current power state + * @ops: client callbacks + * @id: client identifier, see enum vga_switcheroo_client_id. + * Determining the id requires the handler, so GPUs are initially + * assigned -1 and later given their true id in vga_switcheroo_enable() + * @active: whether the outputs are currently switched to this client + * @driver_power_control: whether power state is controlled by the driver's + * runtime pm. If true, writing ON and OFF to the vga_switcheroo debugfs + * interface is a no-op so as not to interfere with runtime pm + * @list: client list + * + * Registered client. A client can be either a GPU or an audio device on a GPU. + * For audio clients, the @fb_info, @active and @driver_power_control members + * are bogus. + */ struct vga_switcheroo_client { struct pci_dev *pdev; struct fb_info *fb_info; @@ -44,10 +110,28 @@ struct vga_switcheroo_client { struct list_head list; }; +/* + * protects access to struct vgasr_priv + */ static DEFINE_MUTEX(vgasr_mutex); +/** + * struct vgasr_priv - vga_switcheroo private data + * @active: whether vga_switcheroo is enabled. + * Prerequisite is the registration of two GPUs and a handler + * @delayed_switch_active: whether a delayed switch is pending + * @delayed_client_id: client to which a delayed switch is pending + * @debugfs_root: directory for vga_switcheroo debugfs interface + * @switch_file: file for vga_switcheroo debugfs interface + * @registered_clients: number of registered GPUs + * (counting only vga clients, not audio clients) + * @clients: list of registered clients + * @handler: registered handler + * + * vga_switcheroo private data. Currently only one vga_switcheroo instance + * per system is supported. + */ struct vgasr_priv { - bool active; bool delayed_switch_active; enum vga_switcheroo_client_id delayed_client_id; @@ -103,6 +187,15 @@ static void vga_switcheroo_enable(void) vgasr_priv.active = true; } +/** + * vga_switcheroo_register_handler() - register handler + * @handler: handler callbacks + * + * Register handler. Enable vga_switcheroo if two vga clients have already + * registered. + * + * Return: 0 on success, -EINVAL if a handler was already registered. + */ int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler) { mutex_lock(&vgasr_mutex); @@ -121,6 +214,11 @@ int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler) } EXPORT_SYMBOL(vga_switcheroo_register_handler); +/** + * vga_switcheroo_unregister_handler() - unregister handler + * + * Unregister handler. Disable vga_switcheroo. + */ void vga_switcheroo_unregister_handler(void) { mutex_lock(&vgasr_mutex); @@ -164,6 +262,19 @@ static int register_client(struct pci_dev *pdev, return 0; } +/** + * vga_switcheroo_register_client - register vga client + * @pdev: client pci device + * @ops: client callbacks + * @driver_power_control: whether power state is controlled by the driver's + * runtime pm + * + * Register vga client (GPU). Enable vga_switcheroo if another GPU and a + * handler have already registered. The power state of the client is assumed + * to be ON. + * + * Return: 0 on success, -ENOMEM on memory allocation error. + */ int vga_switcheroo_register_client(struct pci_dev *pdev, const struct vga_switcheroo_client_ops *ops, bool driver_power_control) @@ -174,6 +285,18 @@ int vga_switcheroo_register_client(struct pci_dev *pdev, } EXPORT_SYMBOL(vga_switcheroo_register_client); +/** + * vga_switcheroo_register_audio_client - register audio client + * @pdev: client pci device + * @ops: client callbacks + * @id: client identifier, see enum vga_switcheroo_client_id + * @active: whether the audio device is fully initialized + * + * Register audio client (audio device on a GPU). The power state of the + * client is assumed to be ON. + * + * Return: 0 on success, -ENOMEM on memory allocation error. + */ int vga_switcheroo_register_audio_client(struct pci_dev *pdev, const struct vga_switcheroo_client_ops *ops, int id, bool active) @@ -215,6 +338,15 @@ find_active_client(struct list_head *head) return NULL; } +/** + * vga_switcheroo_get_client_state() - obtain power state of a given client + * @pdev: client pci device + * + * Obtain power state of a given client as seen from vga_switcheroo. + * The function is only called from hda_intel.c. + * + * Return: Power state. + */ int vga_switcheroo_get_client_state(struct pci_dev *pdev) { struct vga_switcheroo_client *client; @@ -228,6 +360,12 @@ int vga_switcheroo_get_client_state(struct pci_dev *pdev) } EXPORT_SYMBOL(vga_switcheroo_get_client_state); +/** + * vga_switcheroo_unregister_client() - unregister client + * @pdev: client pci device + * + * Unregister client. Disable vga_switcheroo if this is a vga client (GPU). + */ void vga_switcheroo_unregister_client(struct pci_dev *pdev) { struct vga_switcheroo_client *client; @@ -249,6 +387,14 @@ void vga_switcheroo_unregister_client(struct pci_dev *pdev) } EXPORT_SYMBOL(vga_switcheroo_unregister_client); +/** + * vga_switcheroo_client_fb_set() - set framebuffer of a given client + * @pdev: client pci device + * @info: framebuffer + * + * Set framebuffer of a given client. The console will be remapped to this + * on switching. + */ void vga_switcheroo_client_fb_set(struct pci_dev *pdev, struct fb_info *info) { @@ -262,6 +408,42 @@ void vga_switcheroo_client_fb_set(struct pci_dev *pdev, } EXPORT_SYMBOL(vga_switcheroo_client_fb_set); +/** + * DOC: Manual switching and manual power control + * + * In this mode of use, the file /sys/kernel/debug/vgaswitcheroo/switch + * can be read to retrieve the current vga_switcheroo state and commands + * can be written to it to change the state. The file appears as soon as + * two GPU drivers and one handler have registered with vga_switcheroo. + * The following commands are understood: + * + * * OFF: Power off the device not in use. + * * ON: Power on the device not in use. + * * IGD: Switch to the integrated graphics device. + * Power on the integrated GPU if necessary, power off the discrete GPU. + * Prerequisite is that no user space processes (e.g. Xorg, alsactl) + * have opened device files of the GPUs or the audio client. If the + * switch fails, the user may invoke lsof(8) or fuser(1) on /dev/dri/ + * and /dev/snd/controlC1 to identify processes blocking the switch. + * * DIS: Switch to the discrete graphics device. + * * DIGD: Delayed switch to the integrated graphics device. + * This will perform the switch once the last user space process has + * closed the device files of the GPUs and the audio client. + * * DDIS: Delayed switch to the discrete graphics device. + * * MIGD: Mux-only switch to the integrated graphics device. + * Does not remap console or change the power state of either gpu. + * If the integrated GPU is currently off, the screen will turn black. + * If it is on, the screen will show whatever happens to be in VRAM. + * Either way, the user has to blindly enter the command to switch back. + * * MDIS: Mux-only switch to the discrete graphics device. + * + * For GPUs whose power state is controlled by the driver's runtime pm, + * the ON and OFF commands are a no-op (see next section). + * + * For muxless machines, the IGD/DIS, DIGD/DDIS and MIGD/MDIS commands + * should not be used. + */ + static int vga_switcheroo_show(struct seq_file *m, void *v) { struct vga_switcheroo_client *client; @@ -559,6 +741,16 @@ fail: return -1; } +/** + * vga_switcheroo_process_delayed_switch() - helper for delayed switching + * + * Process a delayed switch if one is pending. DRM drivers should call this + * from their ->lastclose callback. + * + * Return: 0 on success. -EINVAL if no delayed switch is pending, if the client + * has unregistered in the meantime or if there are other clients blocking the + * switch. If the actual switch fails, an error is reported and 0 is returned. + */ int vga_switcheroo_process_delayed_switch(void) { struct vga_switcheroo_client *client; @@ -589,6 +781,39 @@ err: } EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch); +/** + * DOC: Driver power control + * + * In this mode of use, the discrete GPU automatically powers up and down at + * the discretion of the driver's runtime pm. On muxed machines, the user may + * still influence the muxer state by way of the debugfs interface, however + * the ON and OFF commands become a no-op for the discrete GPU. + * + * This mode is the default on Nvidia HybridPower/Optimus and ATI PowerXpress. + * Specifying nouveau.runpm=0, radeon.runpm=0 or amdgpu.runpm=0 on the kernel + * command line disables it. + * + * When the driver decides to power up or down, it notifies vga_switcheroo + * thereof so that it can (a) power the audio device on the GPU up or down, + * and (b) update its internal power state representation for the device. + * This is achieved by vga_switcheroo_set_dynamic_switch(). + * + * After the GPU has been suspended, the handler needs to be called to cut + * power to the GPU. Likewise it needs to reinstate power before the GPU + * can resume. This is achieved by vga_switcheroo_init_domain_pm_ops(), + * which augments the GPU's suspend/resume functions by the requisite + * calls to the handler. + * + * When the audio device resumes, the GPU needs to be woken. This is achieved + * by vga_switcheroo_init_domain_pm_optimus_hdmi_audio(), which augments the + * audio device's resume function. + * + * On muxed machines, if the mux is initially switched to the discrete GPU, + * the user ends up with a black screen when the GPU powers down after boot. + * As a workaround, the mux is forced to the integrated GPU on runtime suspend, + * cf. https://bugs.freedesktop.org/show_bug.cgi?id=75917 + */ + static void vga_switcheroo_power_switch(struct pci_dev *pdev, enum vga_switcheroo_state state) { @@ -607,8 +832,17 @@ static void vga_switcheroo_power_switch(struct pci_dev *pdev, vgasr_priv.handler->power_state(client->id, state); } -/* force a PCI device to a certain state - mainly to turn off audio clients */ - +/** + * vga_switcheroo_set_dynamic_switch() - helper for driver power control + * @pdev: client pci device + * @dynamic: new power state + * + * Helper for GPUs whose power state is controlled by the driver's runtime pm. + * When the driver decides to power up or down, it notifies vga_switcheroo + * thereof using this helper so that it can (a) power the audio device on + * the GPU up or down, and (b) update its internal power state representation + * for the device. + */ void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev, enum vga_switcheroo_state dynamic) { @@ -654,8 +888,18 @@ static int vga_switcheroo_runtime_resume(struct device *dev) return 0; } -/* this version is for the case where the power switch is separate - to the device being powered down. */ +/** + * vga_switcheroo_init_domain_pm_ops() - helper for driver power control + * @dev: vga client device + * @domain: power domain + * + * Helper for GPUs whose power state is controlled by the driver's runtime pm. + * After the GPU has been suspended, the handler needs to be called to cut + * power to the GPU. Likewise it needs to reinstate power before the GPU + * can resume. To this end, this helper augments the suspend/resume functions + * by the requisite calls to the handler. It needs only be called on platforms + * where the power switch is separate to the device being powered down. + */ int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain) { @@ -709,6 +953,19 @@ static int vga_switcheroo_runtime_resume_hdmi_audio(struct device *dev) return ret; } +/** + * vga_switcheroo_init_domain_pm_optimus_hdmi_audio() - helper for driver + * power control + * @dev: audio client device + * @domain: power domain + * + * Helper for GPUs whose power state is controlled by the driver's runtime pm. + * When the audio device resumes, the GPU needs to be woken. This helper + * augments the audio device's resume function to do that. + * + * Return: 0 on success, -EINVAL if no power management operations are + * defined for this device. + */ int vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev, struct dev_pm_domain *domain) diff --git a/include/linux/vga_switcheroo.h b/include/linux/vga_switcheroo.h index b483abd34493..fe90bfc3b510 100644 --- a/include/linux/vga_switcheroo.h +++ b/include/linux/vga_switcheroo.h @@ -1,10 +1,31 @@ /* + * vga_switcheroo.h - Support for laptop with dual GPU using one set of outputs + * * Copyright (c) 2010 Red Hat Inc. * Author : Dave Airlie <airlied@redhat.com> * - * Licensed under GPLv2 + * Copyright (c) 2015 Lukas Wunner <lukas@wunner.de> + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS + * IN THE SOFTWARE. * - * vga_switcheroo.h - Support for laptop with dual GPU using one set of outputs */ #ifndef _LINUX_VGA_SWITCHEROO_H_ @@ -14,6 +35,20 @@ struct pci_dev; +/** + * enum vga_switcheroo_state - client power state + * @VGA_SWITCHEROO_OFF: off + * @VGA_SWITCHEROO_ON: on + * @VGA_SWITCHEROO_INIT: client has registered with vga_switcheroo but + * vga_switcheroo is not enabled, i.e. no second client or no handler + * has registered. Only used in vga_switcheroo_get_client_state() which + * in turn is only called from hda_intel.c + * @VGA_SWITCHEROO_NOT_FOUND: client has not registered with vga_switcheroo. + * Only used in vga_switcheroo_get_client_state() which in turn is only + * called from hda_intel.c + * + * Client power state. + */ enum vga_switcheroo_state { VGA_SWITCHEROO_OFF, VGA_SWITCHEROO_ON, @@ -22,20 +57,64 @@ enum vga_switcheroo_state { VGA_SWITCHEROO_NOT_FOUND, }; +/** + * enum vga_switcheroo_client_id - client identifier + * @VGA_SWITCHEROO_IGD: integrated graphics device + * @VGA_SWITCHEROO_DIS: discrete graphics device + * @VGA_SWITCHEROO_MAX_CLIENTS: currently no more than two GPUs are supported + * + * Client identifier. Audio clients use the same identifier & 0x100. + */ enum vga_switcheroo_client_id { VGA_SWITCHEROO_IGD, VGA_SWITCHEROO_DIS, VGA_SWITCHEROO_MAX_CLIENTS, }; +/** + * struct vga_switcheroo_handler - handler callbacks + * @init: initialize handler. + * Optional. This gets called when vga_switcheroo is enabled, i.e. when + * two vga clients have registered. It allows the handler to perform + * some delayed initialization that depends on the existence of the + * vga clients. Currently only the radeon and amdgpu drivers use this. + * The return value is ignored + * @switchto: switch outputs to given client. + * Mandatory. For muxless machines this should be a no-op. Returning 0 + * denotes success, anything else failure (in which case the switch is + * aborted) + * @power_state: cut or reinstate power of given client. + * Optional. The return value is ignored + * @get_client_id: determine if given pci device is integrated or discrete GPU. + * Mandatory + * + * Handler callbacks. The multiplexer itself. The @switchto and @get_client_id + * methods are mandatory, all others may be set to NULL. + */ struct vga_switcheroo_handler { + int (*init)(void); int (*switchto)(enum vga_switcheroo_client_id id); int (*power_state)(enum vga_switcheroo_client_id id, enum vga_switcheroo_state state); - int (*init)(void); int (*get_client_id)(struct pci_dev *pdev); }; +/** + * struct vga_switcheroo_client_ops - client callbacks + * @set_gpu_state: do the equivalent of suspend/resume for the card. + * Mandatory. This should not cut power to the discrete GPU, + * which is the job of the handler + * @reprobe: poll outputs. + * Optional. This gets called after waking the GPU and switching + * the outputs to it + * @can_switch: check if the device is in a position to switch now. + * Mandatory. The client should return false if a user space process + * has one of its device files open + * + * Client callbacks. A client can be either a GPU or an audio device on a GPU. + * The @set_gpu_state and @can_switch methods are mandatory, @reprobe may be + * set to NULL. For audio clients, the @reprobe member is bogus. + */ struct vga_switcheroo_client_ops { void (*set_gpu_state)(struct pci_dev *dev, enum vga_switcheroo_state); void (*reprobe)(struct pci_dev *dev); |