Hi Tomi,
Thank you for the patch.
On Tue, Nov 24, 2020 at 02:45:16PM +0200, Tomi Valkeinen wrote:
> If the PLL calc function is given bad parameters, n_start/m_start may be
> higher than n_stop/m_stop, which leads to the loops iterating through
> the whole u32 number space.
>
> Fix this by failing early on such cases.
>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/omapdrm/dss/pll.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/gpu/drm/omapdrm/dss/pll.c b/drivers/gpu/drm/omapdrm/dss/pll.c
> index 1212f3cc52d1..12926218c436 100644
> --- a/drivers/gpu/drm/omapdrm/dss/pll.c
> +++ b/drivers/gpu/drm/omapdrm/dss/pll.c
> @@ -222,6 +222,9 @@ bool dss_pll_calc_a(const struct dss_pll *pll, unsigned long clkin,
> n_stop = min((unsigned)(clkin / fint_hw_min), hw->n_max);
> n_inc = 1;
>
> + if (n_start > n_stop)
> + return false;
> +
> if (hw->errata_i886) {
> swap(n_start, n_stop);
> n_inc = -1;
> @@ -239,6 +242,9 @@ bool dss_pll_calc_a(const struct dss_pll *pll, unsigned long clkin,
> hw->m_max);
> m_inc = 1;
>
> + if (m_start > m_stop)
> + continue;
> +
> if (hw->errata_i886) {
> swap(m_start, m_stop);
> m_inc = -1;
--
Regards,
Laurent Pinchart
