[PATCH v4] vga_switcheroo: Add helper for deferred probing
Lukas Wunner
lukas at wunner.de
Thu May 19 14:39:16 UTC 2016
So far we've got one condition when DRM drivers need to defer probing
on a dual GPU system and it's coded separately into each of the relevant
drivers. As suggested by Daniel Vetter, deduplicate that code in the
drivers and move it to a new vga_switcheroo helper. This yields better
encapsulation of concepts and lets us add further checks in a central
place. (The existing check pertains to pre-retina MacBook Pros and an
additional check is expected to be needed for retinas.)
v2: This helper could eventually be used by audio clients as well,
so rephrase kerneldoc to refer to "client" instead of "GPU"
and move the single existing check in an if block specific
to PCI_CLASS_DISPLAY_VGA devices. Move documentation on
that check from kerneldoc to a comment. (Daniel Vetter)
v3: Mandate in kerneldoc that registration of client shall only
happen after calling this helper. (Daniel Vetter)
v4: Rebase on 412c8f7de011 ("drm/radeon: Return -EPROBE_DEFER when
amdkfd not loaded")
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: Ben Skeggs <bskeggs at redhat.com>
Cc: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Lukas Wunner <lukas at wunner.de>
---
drivers/gpu/drm/i915/i915_drv.c | 10 +---------
drivers/gpu/drm/nouveau/nouveau_drm.c | 10 +---------
drivers/gpu/drm/radeon/radeon_drv.c | 10 +---------
drivers/gpu/vga/vga_switcheroo.c | 34 ++++++++++++++++++++++++++++++++--
include/linux/vga_switcheroo.h | 2 ++
5 files changed, 37 insertions(+), 29 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index dba03c0..61bf5a9 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -35,11 +35,9 @@
#include "i915_trace.h"
#include "intel_drv.h"
-#include <linux/apple-gmux.h>
#include <linux/console.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
-#include <linux/vgaarb.h>
#include <linux/vga_switcheroo.h>
#include <drm/drm_crtc_helper.h>
@@ -1030,13 +1028,7 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
if (PCI_FUNC(pdev->devfn))
return -ENODEV;
- /*
- * apple-gmux is needed on dual GPU MacBook Pro
- * to probe the panel if we're the inactive GPU.
- */
- if (IS_ENABLED(CONFIG_VGA_ARB) && IS_ENABLED(CONFIG_VGA_SWITCHEROO) &&
- apple_gmux_present() && pdev != vga_default_device() &&
- !vga_switcheroo_handler_flags())
+ if (vga_switcheroo_client_probe_defer(pdev))
return -EPROBE_DEFER;
return drm_get_pci_dev(pdev, ent, &driver);
diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index db5c7d0..a0bb1d0 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -22,13 +22,11 @@
* Authors: Ben Skeggs
*/
-#include <linux/apple-gmux.h>
#include <linux/console.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/pm_runtime.h>
-#include <linux/vgaarb.h>
#include <linux/vga_switcheroo.h>
#include "drmP.h"
@@ -315,13 +313,7 @@ static int nouveau_drm_probe(struct pci_dev *pdev,
bool boot = false;
int ret;
- /*
- * apple-gmux is needed on dual GPU MacBook Pro
- * to probe the panel if we're the inactive GPU.
- */
- if (IS_ENABLED(CONFIG_VGA_ARB) && IS_ENABLED(CONFIG_VGA_SWITCHEROO) &&
- apple_gmux_present() && pdev != vga_default_device() &&
- !vga_switcheroo_handler_flags())
+ if (vga_switcheroo_client_probe_defer(pdev))
return -EPROBE_DEFER;
/* remove conflicting drivers (vesafb, efifb etc) */
diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index b55aa74..a455dc7 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -34,11 +34,9 @@
#include "radeon_drv.h"
#include <drm/drm_pciids.h>
-#include <linux/apple-gmux.h>
#include <linux/console.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
-#include <linux/vgaarb.h>
#include <linux/vga_switcheroo.h>
#include <drm/drm_gem.h>
@@ -340,13 +338,7 @@ static int radeon_pci_probe(struct pci_dev *pdev,
if (ret == -EPROBE_DEFER)
return ret;
- /*
- * apple-gmux is needed on dual GPU MacBook Pro
- * to probe the panel if we're the inactive GPU.
- */
- if (IS_ENABLED(CONFIG_VGA_ARB) && IS_ENABLED(CONFIG_VGA_SWITCHEROO) &&
- apple_gmux_present() && pdev != vga_default_device() &&
- !vga_switcheroo_handler_flags())
+ if (vga_switcheroo_client_probe_defer(pdev))
return -EPROBE_DEFER;
/* Get rid of things like offb */
diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index cbd7c98..101e14c 100644
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -30,6 +30,7 @@
#define pr_fmt(fmt) "vga_switcheroo: " fmt
+#include <linux/apple-gmux.h>
#include <linux/console.h>
#include <linux/debugfs.h>
#include <linux/fb.h>
@@ -308,7 +309,8 @@ static int register_client(struct pci_dev *pdev,
*
* 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.
+ * to be ON. Beforehand, vga_switcheroo_client_probe_defer() shall be called
+ * to ensure that all prerequisites are met.
*
* Return: 0 on success, -ENOMEM on memory allocation error.
*/
@@ -329,7 +331,8 @@ EXPORT_SYMBOL(vga_switcheroo_register_client);
* @id: client identifier
*
* Register audio client (audio device on a GPU). The power state of the
- * client is assumed to be ON.
+ * client is assumed to be ON. Beforehand, vga_switcheroo_client_probe_defer()
+ * shall be called to ensure that all prerequisites are met.
*
* Return: 0 on success, -ENOMEM on memory allocation error.
*/
@@ -376,6 +379,33 @@ find_active_client(struct list_head *head)
}
/**
+ * vga_switcheroo_client_probe_defer() - whether to defer probing a given client
+ * @pdev: client pci device
+ *
+ * Determine whether any prerequisites are not fulfilled to probe a given
+ * client. Drivers shall invoke this early on in their ->probe callback
+ * and return %-EPROBE_DEFER if it evaluates to %true. Thou shalt not
+ * register the client ere thou hast called this.
+ *
+ * Return: %true if probing should be deferred, otherwise %false.
+ */
+bool vga_switcheroo_client_probe_defer(struct pci_dev *pdev)
+{
+ if ((pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA) {
+ /*
+ * apple-gmux is needed on pre-retina MacBook Pro
+ * to probe the panel if pdev is the inactive GPU.
+ */
+ if (apple_gmux_present() && pdev != vga_default_device() &&
+ !vgasr_priv.handler_flags)
+ return true;
+ }
+
+ return false;
+}
+EXPORT_SYMBOL(vga_switcheroo_client_probe_defer);
+
+/**
* vga_switcheroo_get_client_state() - obtain power state of a given client
* @pdev: client pci device
*
diff --git a/include/linux/vga_switcheroo.h b/include/linux/vga_switcheroo.h
index b39a5f3..960bedb 100644
--- a/include/linux/vga_switcheroo.h
+++ b/include/linux/vga_switcheroo.h
@@ -165,6 +165,7 @@ int vga_switcheroo_unlock_ddc(struct pci_dev *pdev);
int vga_switcheroo_process_delayed_switch(void);
+bool vga_switcheroo_client_probe_defer(struct pci_dev *pdev);
enum vga_switcheroo_state vga_switcheroo_get_client_state(struct pci_dev *dev);
void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev, enum vga_switcheroo_state dynamic);
@@ -188,6 +189,7 @@ static inline enum vga_switcheroo_handler_flags_t vga_switcheroo_handler_flags(v
static inline int vga_switcheroo_lock_ddc(struct pci_dev *pdev) { return -ENODEV; }
static inline int vga_switcheroo_unlock_ddc(struct pci_dev *pdev) { return -ENODEV; }
static inline int vga_switcheroo_process_delayed_switch(void) { return 0; }
+static inline bool vga_switcheroo_client_probe_defer(struct pci_dev *pdev) { return false; }
static inline enum vga_switcheroo_state vga_switcheroo_get_client_state(struct pci_dev *dev) { return VGA_SWITCHEROO_ON; }
static inline void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev, enum vga_switcheroo_state dynamic) {}
--
2.8.1
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