diff options
Diffstat (limited to 'Documentation/DocBook/drm.tmpl')
| -rw-r--r-- | Documentation/DocBook/drm.tmpl | 118 |
1 files changed, 70 insertions, 48 deletions
diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl index 91ee107d5d0e..a6080941f5e4 100644 --- a/Documentation/DocBook/drm.tmpl +++ b/Documentation/DocBook/drm.tmpl @@ -186,11 +186,12 @@ <varlistentry> <term>DRIVER_HAVE_IRQ</term><term>DRIVER_IRQ_SHARED</term> <listitem><para> - DRIVER_HAVE_IRQ indicates whether the driver has an IRQ handler. The - DRM core will automatically register an interrupt handler when the - flag is set. DRIVER_IRQ_SHARED indicates whether the device & - handler support shared IRQs (note that this is required of PCI - drivers). + DRIVER_HAVE_IRQ indicates whether the driver has an IRQ handler + managed by the DRM Core. The core will support simple IRQ handler + installation when the flag is set. The installation process is + described in <xref linkend="drm-irq-registration"/>.</para> + <para>DRIVER_IRQ_SHARED indicates whether the device & handler + support shared IRQs (note that this is required of PCI drivers). </para></listitem> </varlistentry> <varlistentry> @@ -344,50 +345,71 @@ char *date;</synopsis> The DRM core tries to facilitate IRQ handler registration and unregistration by providing <function>drm_irq_install</function> and <function>drm_irq_uninstall</function> functions. Those functions only - support a single interrupt per device. - </para> - <!--!Fdrivers/char/drm/drm_irq.c drm_irq_install--> - <para> - Both functions get the device IRQ by calling - <function>drm_dev_to_irq</function>. This inline function will call a - bus-specific operation to retrieve the IRQ number. For platform devices, - <function>platform_get_irq</function>(..., 0) is used to retrieve the - IRQ number. - </para> - <para> - <function>drm_irq_install</function> starts by calling the - <methodname>irq_preinstall</methodname> driver operation. The operation - is optional and must make sure that the interrupt will not get fired by - clearing all pending interrupt flags or disabling the interrupt. - </para> - <para> - The IRQ will then be requested by a call to - <function>request_irq</function>. If the DRIVER_IRQ_SHARED driver - feature flag is set, a shared (IRQF_SHARED) IRQ handler will be - requested. - </para> - <para> - The IRQ handler function must be provided as the mandatory irq_handler - driver operation. It will get passed directly to - <function>request_irq</function> and thus has the same prototype as all - IRQ handlers. It will get called with a pointer to the DRM device as the - second argument. - </para> - <para> - Finally the function calls the optional - <methodname>irq_postinstall</methodname> driver operation. The operation - usually enables interrupts (excluding the vblank interrupt, which is - enabled separately), but drivers may choose to enable/disable interrupts - at a different time. - </para> - <para> - <function>drm_irq_uninstall</function> is similarly used to uninstall an - IRQ handler. It starts by waking up all processes waiting on a vblank - interrupt to make sure they don't hang, and then calls the optional - <methodname>irq_uninstall</methodname> driver operation. The operation - must disable all hardware interrupts. Finally the function frees the IRQ - by calling <function>free_irq</function>. + support a single interrupt per device, devices that use more than one + IRQs need to be handled manually. </para> + <sect4> + <title>Managed IRQ Registration</title> + <para> + Both the <function>drm_irq_install</function> and + <function>drm_irq_uninstall</function> functions get the device IRQ by + calling <function>drm_dev_to_irq</function>. This inline function will + call a bus-specific operation to retrieve the IRQ number. For platform + devices, <function>platform_get_irq</function>(..., 0) is used to + retrieve the IRQ number. + </para> + <para> + <function>drm_irq_install</function> starts by calling the + <methodname>irq_preinstall</methodname> driver operation. The operation + is optional and must make sure that the interrupt will not get fired by + clearing all pending interrupt flags or disabling the interrupt. + </para> + <para> + The IRQ will then be requested by a call to + <function>request_irq</function>. If the DRIVER_IRQ_SHARED driver + feature flag is set, a shared (IRQF_SHARED) IRQ handler will be + requested. + </para> + <para> + The IRQ handler function must be provided as the mandatory irq_handler + driver operation. It will get passed directly to + <function>request_irq</function> and thus has the same prototype as all + IRQ handlers. It will get called with a pointer to the DRM device as the + second argument. + </para> + <para> + Finally the function calls the optional + <methodname>irq_postinstall</methodname> driver operation. The operation + usually enables interrupts (excluding the vblank interrupt, which is + enabled separately), but drivers may choose to enable/disable interrupts + at a different time. + </para> + <para> + <function>drm_irq_uninstall</function> is similarly used to uninstall an + IRQ handler. It starts by waking up all processes waiting on a vblank + interrupt to make sure they don't hang, and then calls the optional + <methodname>irq_uninstall</methodname> driver operation. The operation + must disable all hardware interrupts. Finally the function frees the IRQ + by calling <function>free_irq</function>. + </para> + </sect4> + <sect4> + <title>Manual IRQ Registration</title> + <para> + Drivers that require multiple interrupt handlers can't use the managed + IRQ registration functions. In that case IRQs must be registered and + unregistered manually (usually with the <function>request_irq</function> + and <function>free_irq</function> functions, or their devm_* equivalent). + </para> + <para> + When manually registering IRQs, drivers must not set the DRIVER_HAVE_IRQ + driver feature flag, and must not provide the + <methodname>irq_handler</methodname> driver operation. They must set the + <structname>drm_device</structname> <structfield>irq_enabled</structfield> + field to 1 upon registration of the IRQs, and clear it to 0 after + unregistering the IRQs. + </para> + </sect4> </sect3> <sect3> <title>Memory Manager Initialization</title> |