Re: [PATCH 1/3] fbdev: omap: use threaded IRQ for LCD DMA

[Helge Deller]

On 1/2/25 22:31, Linus Walleij wrote:
> On Thu, Jan 2, 2025 at 7:20 PM Aaro Koskinen <aaro.koskinen@xxxxxx> wrote:
>
> > When using touchscreen and framebuffer, Nokia 770 crashes easily with:
> >
> >      BUG: scheduling while atomic: irq/144-ads7846/82/0x00010000
> >      Modules linked in: usb_f_ecm g_ether usb_f_rndis u_ether libcomposite configfs omap_udc ohci_omap ohci_hcd
> >      CPU: 0 UID: 0 PID: 82 Comm: irq/144-ads7846 Not tainted 6.12.7-770 #2
> >      Hardware name: Nokia 770
> >      Call trace:
> >       unwind_backtrace from show_stack+0x10/0x14
> >       show_stack from dump_stack_lvl+0x54/0x5c
> >       dump_stack_lvl from __schedule_bug+0x50/0x70
> >       __schedule_bug from __schedule+0x4d4/0x5bc
> >       __schedule from schedule+0x34/0xa0
> >       schedule from schedule_preempt_disabled+0xc/0x10
> >       schedule_preempt_disabled from __mutex_lock.constprop.0+0x218/0x3b4
> >       __mutex_lock.constprop.0 from clk_prepare_lock+0x38/0xe4
> >       clk_prepare_lock from clk_set_rate+0x18/0x154
> >       clk_set_rate from sossi_read_data+0x4c/0x168
> >       sossi_read_data from hwa742_read_reg+0x5c/0x8c
> >       hwa742_read_reg from send_frame_handler+0xfc/0x300
> >       send_frame_handler from process_pending_requests+0x74/0xd0
> >       process_pending_requests from lcd_dma_irq_handler+0x50/0x74
> >       lcd_dma_irq_handler from __handle_irq_event_percpu+0x44/0x130
> >       __handle_irq_event_percpu from handle_irq_event+0x28/0x68
> >       handle_irq_event from handle_level_irq+0x9c/0x170
> >       handle_level_irq from generic_handle_domain_irq+0x2c/0x3c
> >       generic_handle_domain_irq from omap1_handle_irq+0x40/0x8c
> >       omap1_handle_irq from generic_handle_arch_irq+0x28/0x3c
> >       generic_handle_arch_irq from call_with_stack+0x1c/0x24
> >       call_with_stack from __irq_svc+0x94/0xa8
> >      Exception stack(0xc5255da0 to 0xc5255de8)
> >      5da0: 00000001 c22fc620 00000000 00000000 c08384a8 c106fc00 00000000 c240c248
> >      5dc0: c113a600 c3f6ec30 00000001 00000000 c22fc620 c5255df0 c22fc620 c0279a94
> >      5de0: 60000013 ffffffff
> >       __irq_svc from clk_prepare_lock+0x4c/0xe4
> >       clk_prepare_lock from clk_get_rate+0x10/0x74
> >       clk_get_rate from uwire_setup_transfer+0x40/0x180
> >       uwire_setup_transfer from spi_bitbang_transfer_one+0x2c/0x9c
> >       spi_bitbang_transfer_one from spi_transfer_one_message+0x2d0/0x664
> >       spi_transfer_one_message from __spi_pump_transfer_message+0x29c/0x498
> >       __spi_pump_transfer_message from __spi_sync+0x1f8/0x2e8
> >       __spi_sync from spi_sync+0x24/0x40
> >       spi_sync from ads7846_halfd_read_state+0x5c/0x1c0
> >       ads7846_halfd_read_state from ads7846_irq+0x58/0x348
> >       ads7846_irq from irq_thread_fn+0x1c/0x78
> >       irq_thread_fn from irq_thread+0x120/0x228
> >       irq_thread from kthread+0xc8/0xe8
> >       kthread from ret_from_fork+0x14/0x28
> >
> > As a quick fix, switch to a threaded IRQ which provides a stable system.
> >
> > Signed-off-by: Aaro Koskinen <aaro.koskinen@xxxxxx>
>
> Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>

applied to linux-fbdev git tree.

Helge