Hi Daniel,
Thanks for improving the documentation :-)
On Sunday 27 January 2013 18:42:16 Daniel Vetter wrote:
Now that the fbdev helper interface for drivers is trimmed down, update the kerneldoc for all the remaining exported functions.
I've tried to beat the DocBook a bit by reordering the function references a bit into a more sensible ordering. But that didn't work out at all. Hence just extend the in-code DOC: section a bit.
Also remove the LOCKING: sections - especially for the setup functions they're totally bogus. But that's not a documentation problem, but simply an artifact of the current rather hazardous locking around drm init and even more so around fbdev setup ...
Please see below for comments (I've reflowed the text to ease review).
v2: Some further improvements:
- Also add documentation for drm_fb_helper_single_add_all_connectors, Dave Airlie didn't want me to kill this one from the fb helper interface.
- Update docs for drm_fb_helper_fill_var/fix - they should be used from the driver's ->fb_probe callback to setup the fbdev info structure.
- Clarify what the ->fb_probe callback should all do - it needs to setup both the fbdev info and allocate the drm framebuffer used as backing storage.
- Add basic documentaation for the drm_fb_helper_funcs driver callback vfunc.
Signed-off-by: Daniel Vetter daniel.vetter@ffwll.ch
moar kerneldoc
Documentation/DocBook/drm.tmpl | 1 + drivers/gpu/drm/drm_fb_helper.c | 146 ++++++++++++++++++++++++++++++++---- include/drm/drm_fb_helper.h | 11 +++ 3 files changed, 143 insertions(+), 15 deletions(-)
diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl index 6c11d77..14ad829 100644 --- a/Documentation/DocBook/drm.tmpl +++ b/Documentation/DocBook/drm.tmpl @@ -2139,6 +2139,7 @@ void intel_crt_init(struct drm_device *dev) <title>fbdev Helper Functions Reference</title> !Pdrivers/gpu/drm/drm_fb_helper.c fbdev helpers !Edrivers/gpu/drm/drm_fb_helper.c +!Iinclude/drm/drm_fb_helper.h </sect2> <sect2> <title>Display Port Helper Functions Reference</title> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 5a92470..a7538cc 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -52,9 +52,34 @@ static LIST_HEAD(kernel_fb_helper_list);
- mode setting driver. They can be used mostly independantely from the
Now that you have removed one of the dependencies on the crtc helpers in your "drm/fb-helper: don't disable everything in initial_config" patch, are there others ? If not you can s/mostly //.
- crtc helper functions used by many drivers to implement the kernel mode
- setting interfaces.
- Initialization is done as a three-step process with
- drm_fb_helper_init(), drm_fb_helper_single_add_all_connectors() and
- drm_fb_helper_initial_config(). Drivers with fancier requirements than
- the default beheviour can override the second step with their own code.
- Teardown is done with drm_fb_helper_fini().
- At runtime drivers should restore the fbdev console by calling
- drm_fb_helper_restore_fbdev_mode() from their ->lastclose callback. They
- can also notify the fb helper code from updates to the output
Is it "can" or "must" ? If "can", in what conditions should they call drm_fb_helper_restore_fbdev_mode() and in what conditions shouldn't they ?
- configuration by calling drm_fb_helper_hotplug_event().
- All other functions exported by the fb helper library can be used to
*/
- implement the fbdev driver interface by the driver.
-/* simple single crtc case helper function */ +/**
- drm_fb_helper_single_add_all_connectors() - add all connectors to fbdev
emulation helper
- @fb_helper: fbdev initialized with drm_fb_helper_init
- This functions adds all the available connectors for use with the given
- fb_helper. This is a separate step to allow drivers to freely assign or
- connectors to the fbdev, e.g. if some are reserved for special purposes
- not adequate to be used for the fbcon.
- Since this is part of the initial setup before the fbdev is published,
- no locking is required.
- */
int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper) { struct drm_device *dev = fb_helper->dev; @@ -163,6 +188,10 @@ static void drm_fb_helper_restore_lut_atomic(struct drm_crtc *crtc) crtc->funcs->gamma_set(crtc, r_base, g_base, b_base, 0, crtc->gamma_size); }
+/**
- drm_fb_helper_debug_enter - implementation for ->fb_debug_enter
- @info: fbdev registered by the helper.
- */
int drm_fb_helper_debug_enter(struct fb_info *info) { struct drm_fb_helper *helper = info->par; @@ -208,6 +237,10 @@ static struct drm_framebuffer *drm_mode_config_fb(struct drm_crtc *crtc) return NULL; }
+/**
- drm_fb_helper_debug_leave - implementation for ->fb_debug_leave
- @info: fbdev registered by the helper.
- */
int drm_fb_helper_debug_leave(struct fb_info *info) { struct drm_fb_helper *helper = info->par; @@ -243,9 +276,9 @@ EXPORT_SYMBOL(drm_fb_helper_debug_leave);
- drm_fb_helper_restore_fbdev_mode - restore fbdev configuration
- @fb_helper: fbcon to restore
- This should be called from driver's drm->lastclose callback when
- implementing an fbcon on top of kms using this helper. This ensures that
- the user isn't greeted with a black screen when e.g. X dies.
- This should be called from driver's drm <code>->lastclose</code>
The resulting HTML is
<code>->lastclose</code>
I'm not sure that's what you want :-)
- callback when implementing an fbcon on top of kms using this helper.
- This ensures that the user isn't greeted with a black screen when e.g.
*/
- X dies.
bool drm_fb_helper_restore_fbdev_mode(struct drm_fb_helper *fb_helper) { @@ -378,6 +411,11 @@ static void drm_fb_helper_dpms(struct fb_info *info, int dpms_mode) drm_modeset_unlock_all(dev); }
+/**
- drm_fb_helper_blank - implementation for ->fb_blank
- @blank: desired blanking state
- @info: fbdev registered by the helper.
Nitpicking here, shouldn't you either use a full stop at the end of each argument, or no full stop at all (this applies to the other functions as well) ?
- */
int drm_fb_helper_blank(int blank, struct fb_info *info) { switch (blank) { @@ -421,6 +459,24 @@ static void drm_fb_helper_crtc_free(struct drm_fb_helper *helper) kfree(helper->crtc_info); }
+/**
- drm_fb_helper_init - initialize a drm_fb_helper structure
- @dev: drm device
- @fb_helper: driver-allocated fbdev helper structure to initialize
- @crtc_count: crtc count
- @max_conn_count: max connector count
- This allocates the structures for the fbdev helper with the given
- limits. Note that this won't yet touch the hw (through the driver
s/hw/hardware/ ?
It might be a good idea to add a small description of the crtc_count parameter.
- interfaces) nor register the fbdev. This is only done in
- drm_fb_helper_initial_config() to allow driver writes more control over
- the exact init sequence.
- Drivers must also set fb_helper->funcs before calling
s/also // ?
- drm_fb_helper_initial_config().
- RETURNS:
- Zero if everything went ok, nonzero otherwise.
- */
int drm_fb_helper_init(struct drm_device *dev, struct drm_fb_helper *fb_helper, int crtc_count, int max_conn_count) @@ -549,6 +605,11 @@ static int setcolreg(struct drm_crtc *crtc, u16 red, u16 green, return 0; }
+/**
- drm_fb_helper_setcmap - implementation for ->fb_setcmap
- @cmap: cmap to set
- @info: fbdev registered by the helper.
- */
int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info) { struct drm_fb_helper *fb_helper = info->par; @@ -588,6 +649,11 @@ int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info) } EXPORT_SYMBOL(drm_fb_helper_setcmap);
+/**
- drm_fb_helper_check_var - implementation for ->fb_check_var
- @var: screeninfo to check
- @info: fbdev registered by the helper.
- */
int drm_fb_helper_check_var(struct fb_var_screeninfo *var, struct fb_info *info) { @@ -680,7 +746,14 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var, } EXPORT_SYMBOL(drm_fb_helper_check_var);
-/* this will let fbcon do the mode init */ +/**
- drm_fb_helper_set_par - implementation for ->fb_set_par
- @info: fbdev registered by the helper.
- This will let fbcon do the mode init and is called at initialization
- time by the fbdev core when registering the driver, and later on
- through the hotplug callback.
- */
int drm_fb_helper_set_par(struct fb_info *info) { struct drm_fb_helper *fb_helper = info->par; @@ -712,6 +785,11 @@ int drm_fb_helper_set_par(struct fb_info *info) } EXPORT_SYMBOL(drm_fb_helper_set_par);
+/**
- drm_fb_helper_pan_display - implementation for ->fb_pan_display
- @var: updated screen information
- @info: fbdev registered by the helper.
- */
int drm_fb_helper_pan_display(struct fb_var_screeninfo *var, struct fb_info *info) { @@ -750,8 +828,9 @@ int drm_fb_helper_pan_display(struct fb_var_screeninfo *var, EXPORT_SYMBOL(drm_fb_helper_pan_display);
/*
- Allocates the backing storage through the ->fb_probe callback and then
- registers the fbdev and sets up the panic notifier.
- Allocates the backing storage and sets up the fbdev info structure
- through the ->fb_probe callback and then registers the fbdev and sets
*/
- up the panic notifier.
static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper, int preferred_bpp) @@ -873,6 +952,19 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper, return 0; }
+/**
- drm_fb_helper_fill_fix - initializes fixed fbdev information
- @info: fbdev registered by the helper.
- @pitch: desired pitch
- @depth: desired depth
- Helper to fill in the fixed fbdev information useful for a
- non-accelerated fbdev emulations. Drivers which support acceleration
- methods which impose additional constraints need to set up their own
- limits.
- Drivers should call this (or their equivalent setup code) from their
- <code>->fb_probe</code> callback.
- */
void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch, uint32_t depth) { @@ -893,6 +985,20 @@ void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch, } EXPORT_SYMBOL(drm_fb_helper_fill_fix);
+/**
- drm_fb_helper_fill_var - initalizes variable fbdev information
- @info: fbdev instance to set up
- @fb_helper: fb helper instance to use as template
- @fb_width: desired fb width
- @fb_height: desired fb height
- Sets up the variable fbdev metainformation from the given fb helper
- instance and the drm framebuffer allocated in
- <code>fb_helper->fb</code>.
- Drivers should call this (or their equivalent setup code) from their
- <code>->fb_probe</code> callback after having allocated the fbdev
- backing storage framebuffer.
- */
void drm_fb_helper_fill_var(struct fb_info *info, struct drm_fb_helper *fb_helper, uint32_t fb_width, uint32_t fb_height) { @@ -1355,18 +1461,23 @@ out: }
/**
- drm_helper_initial_config - setup a sane initial connector configuration
- drm_fb_helper_initial_config - setup a sane initial connector
configuration
- @fb_helper: fb_helper device struct
- @bpp_sel: bpp value to use for the framebuffer configuration
- LOCKING:
- Called at init time by the driver to set up the @fb_helper initial
- configuration, must take the mode config lock.
- Scans the CRTCs and connectors and tries to put together an initial
- setup. At the moment, this is a cloned configuration across all heads
- with a new framebuffer object as the backing store.
- Note that this also registers the fbdev and so allows userspace to call
- into the driver through the fbdev interfaces.
- This function will call down into the <code>->fb_probe</code> callback
<code> is displayed in the resulting HTML here as well.
- to let the driver allocate and initialize the fbdev info structure and
- the drm framebuffer used to back the fbdev. drm_fb_helper_fill_var()
- and drm_fb_helper_fill_fix() are provided as helpers to setup simple
- default values for the fbdev info structure.
*/
- RETURNS:
- Zero if everything went ok, nonzero otherwise.
@@ -1397,12 +1508,17 @@ EXPORT_SYMBOL(drm_fb_helper_initial_config);
probing all the outputs attached to the fb- @fb_helper: the drm_fb_helper
- LOCKING:
- Called at runtime, must take mode config lock.
- Scan the connectors attached to the fb_helper and try to put together a
- setup after *notification of a change in output configuration.
- Called at runtime, takes the mode config locks to be able to
- check/change the modeset configuration. Must be run from process
- context (which usually means either the output polling work or a work
- item launch from the driver's hotplug interrupt).
s/launch/launched/
- Note that the driver must ensure that this is only called _after_ the fb
- has been fully set up, i.e. after the call to
- drm_fb_helper_initial_config.
*/
- RETURNS:
- 0 on success and a non-zero error code otherwise.
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h index 973402d..3c30297 100644 --- a/include/drm/drm_fb_helper.h +++ b/include/drm/drm_fb_helper.h @@ -48,6 +48,17 @@ struct drm_fb_helper_surface_size { u32 surface_depth; };
+/**
- struct drm_fb_helper_funcs - driver callbacks for the fbdev emulation
library
- @gamma_set: - Set the given lut register on the given crtc.
- @gamma_get: - Read the given lut register on the given crtc, used to
safe the
s/lut/gamma lut/ ?
current lut when force-restoring the fbdev for e.g. kdbg.
- @fb_probe: - Driver callback to allocate and initialize the fbdev info
structure. Futhermore it also needs to allocate the drm
framebuffer used to back the fbdev.
- Driver callbacks used by the fbdev emulation helper library.
- */
struct drm_fb_helper_funcs { void (*gamma_set)(struct drm_crtc *crtc, u16 red, u16 green, u16 blue, int regno);