On Mon, 18 Nov 2019 17:38:49 +0100, Pierre-Louis Bossart wrote: > > > > On 11/17/19 2:53 AM, Takashi Iwai wrote: > > Many PCI and other drivers performs snd_pcm_period_elapsed() simply in > > its interrupt handler, so the sync_stop operation is just to call > > synchronize_irq(). Instead of putting this call multiple times, > > introduce the common card->sync_irq field. When this field is set, > > PCM core performs synchronize_irq() for sync-stop operation. Each > > driver just needs to copy its local IRQ number to card->sync_irq, and > > that's all we need. > > Maybe a red-herring or complete non-sense, but I wonder if this is > going to get in the way of Ranjani's multi-client work, where we could > have multiple cards created but with a single IRQ handled by the > parent PCI device? > > Ranjani, you may want to double-check this and chime in, thanks! The synchronize_irq() is fairly safe to call multiple times, and I don't think any problem by invoking it for multi-clients sharing the same IRQ. For example, Digigram miXart driver creates multiple card objects from a single PCI entry, and I already thought of that possibility; they set the same card->sync_irq value to all card objects, which eventually will call synchronize_irq() multiple times. From the performance POV, this shouldn't be a big problem, because the place calling this is only at hw_params, prepare and hw_free, neither are hot-path. thanks, Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
